I've compiled this list of tips for making an ecommerce store better and increasing conversion rates from a WebmasterWorld thread.

FRONT PAGE

1. Things to include above the "fold" on the front page
• Identify the site
• Engender confidence. One spelling mistake and you're dead.
• Show the site's purpose (if it's a commerce site, make that clear)
• Show a few best-sellers to grab the customer
• Show at least one sale item "this week" or a new hot product (to grab old customers)
2. Somewhere, not necessarily above the fold, should contain clear site navigation with links to cart, FAQs, email sign-up, policies and contact info which should ideally be a prominent #800.
3. Front page should contain some key word text for search engines and the page should load fairly fast.

TRUST

1. My golden rule…portray trust and credibility to instill confidence within the shopper to make a purchase.
2. Include "points of reassurance" by every "point of action". Ex. – if you are requesting that someone provide you with their e-mail address, clearly state that their privacy is important to you and you will not share that information with any other companies.
3. Use SSL and make sure the user knows you’re using it.
4. Subscribe to a service like VeriSign, Thawte or ScanAlert. Prominently place these logos to reassure your customer that you care about the security of their information.
5. Have a clearly defined privacy policy.
6. Include your physical address on your site.
7. Define your return policy.
8. Use real customer testimonials with authentic customer photos…no stock photography.
9. Have a short testimonial right at the top or prominent position in a dashed box.
10. Make sure to include an "About Us" section on your site. The majority of my customers visit this section before making a purchase.

SUPPORT

1. If you don't have one an 800 number, add one, it will increase your sales 30% plus.
2. Don’t just get a toll-free number, but make sure the placement of that number on your site is prominent and consistent.
3. Another thing regarding 800 numbers Specify the exact working ours for your 800 service near the number.
4. Place a "Click here if you need help placing your order" link on each page in a prominent place. When clicked a pop up opens with detailed instruction on every step of the purchase.
5. Have a link 'ask a question about this product' which opens an email with the product number in the subject line.
6. Another thing regarding customer questions, When a customer wants to ask a question about specific products it's very important to be able to give the answer quick...a contact form is nice but its not quick enough...check your emails and talk to your customer service staff ..grab information about specific products that people usually ask about and put a clear "FAQ About this product" button. on the product page. The trust you build when answering question quick is huge and will convert to sales!
7. Always answer customer emails quickly.

BUY BUTTON

1. Change the wording of your 'Buy' buttons to 'Add to Cart'. Buy Now implies a much higher commitment level that they may not be ready for, coax them and make them comfortable before getting a commitment.
2. Increase the size of your "buy" button to a size you are uncomfortable with in your layout and make it a color that sticks out "red". Believe it or not this can add 1% - 5% in your sales.
3. Don’t always concentrate on just making the "buy now" buttons the most prominent on every page, but rather concentrate on styling the "primary action" buttons the most prominently on every page. Ex. – you sell MP3 players, and you provide the ability for customers to select a few players and compare them before they can buy now. Make that "compare" the same style as you would the "buy now" button on a page in which the "buy now" button exists. This will help herd customers through your sales funnel.
4. Keep your "buy now" button consistently and prominently placed on all product pages. The closer to the top of the page…the better. I have 2 cheesy sayings for this. 1. "Above the fold if you want it sold" & 2. "Eye level is buy level"

USABILITY

1. Make your site is usable. No need for horizontal scrolling, excessive vertical scrolling or intrusive pop-up windows.
2. Make your checkout process as usable, intuitive, reassuring and simple as possible. Losing someone during your checkout process is a CRITICAL loss.
3. Remove distractions from the checkout process such as the main nav that existed during the shopping portion of your site.
4. Provide a checkout process indicator. If your checkout process has 3 steps, indicate what step they are on and how many steps there are.
5. Try to keep font text at 12pt or larger whenever possible.
6. Offer an enlargement photo/s of the product, and make it/them BIG.
7. Provide clear images of your products.
8. Don’t force people to install any crazy plug-ins just to make a purchase from your site. Stick with Flash, javascript, and the other breads & butters.
9. Do not cross sell much lesser items, it just distracts them. Get them to check out and sell other items in the confirmation email and within a mailer sent with the product.
10. If you offer a lot of products, allows users to sort them by important criteria…price, size, color, etc.
11. If you offer products that are similar but have slight differences between the different grades/models or are from multiple suppliers (ex. digicams or cordless drills) develop a comparison tool that will allow customers to choose and compare products.
12. Use a custom 404 page to link people to the important areas of your site
13. Don’t use "clever" names for your shopping cart like "wicker basket" or "widget box".
14. Provide shopping instructions in an empty cart. Don’t just say "your cart is empty"
15. Your customers should not have to search for something for more that 3-5 seconds. Ensure that all of your action buttons are easy to see and jump out to the customer. Also, make site navigation intuitive so it is not difficult to find things.
16. No purchase should be more that 2 clicks away. The more a customer has to click to get to a product and add it to their cart, the less likely they will buy.
17. Winnow/Categorize products under labels the customer will quickly and easily identify. You can (and should) use more than one way to arrive at the same page.
18. Make links blue and underlined - People know they are clickable! Don't make people think or wonder if something is clickable.
19. Place different types of specifications in their own boxes. Make it easy for people to read, because you need to make them read, and it is really hard to make them do it.

FORMS

1. Don’t make people type their e-mail address twice.
2. Don’t use a drop-down for the "state" list in your order form. With all of the scrolling mice people use these days, many people are sure to accidentally scroll off of their correct state. If state is not required for computing taxes then use a text input field. Its much easier to recognize Dalaware as Delaware when someone makes a type-o then it is to recognize Georgia as Delaware when someone accidentally scrolls with their mouse when focus is left on the form field. Most usability books that I have read (including NNG) concur.
3. Give customers the opportunity to copy their shipping info to their billing info if they are identical.
4. Clearly identify what info in your checkout process is required.
5. If you are going to use error messages, make them friendly and easy to understand. No "INCORRECT USER INPUT IN PHONE FIELD!" messages.
6. If your checkout error messages occur on a page other than the page with the errors, preserve the information that the user has already input.
7. Don’t make the user specify a choice when there is only 1 "choice". If it only comes on blue, don’t make them select the "blue" radio button or choose "blue" from the drop down.
8. Remove all unneeded data collection (i.e. customer phone numbers and fax numbers - do you really need them?)
9. Don't just say "CVV code" when you want the "3-digit code on the white strip on the back of your credit card."
10. Make sure your credit card input field allows the user to input spaces/dashes or whatever they want, then parse that data before passing it on. Throwing invalid credit card numbers can deter sales.

PRICES / SHIPPING / CHECK OUT

1. Clearly display your prices and shipping charges and tax BEFORE the checkout process is completed.
2. Don’t use complex formulas for shipping prices like if you buy 12.2 pounds worth of these, and then multiply that weight by this shipping rate. Show them the price.
3. Consider making shipping free
4. Display the stock status of your items and do so BEFORE the user puts the item in their cart.
5. Estimate the delivery time
6. Accept a variety of payment methods and clearly display what those methods are.
7. Allow customer to make a purchase without having to register with your site.
8. Make the price of the product stick out, make it Big and Bold. Good for up to another 2% in sales
9. When someone adds something to their cart, take THEM THERE and show the cart, just adding a little indicator is confusing.
10. Make a summary of the cart available on all page which includes a total including shipping as well as clear buttons/links to view the cart and/or go to the checkout.
11. Make the check out quick and easy, the least amount of pages the better.

COPY

1. Do a spelling check on your site. There aren’t many things more unprofessional than spelling errErs.
2. Read your copy, make sure its compelling, yet not exaggerated.
3. Identify your USP (unique selling proposition) and exploit it. If you are the only seller of medium-sized green widgets in the US…state it and be proud of it.
4. Don’t just focus on the features of your product, but rather on the benefits those features provide to your customers. Don’t just say "folding green widgets", say "Our folding green widgets will save you valuable space in your garage".
5. Consider making every link the last part of the statement "I want to". In other words, don’t just have a link that says "privacy policy", but rather "read the privacy policy". Do you get it….I want to "Read the Privacy Policy".
6. Don’t make important information look like ads. There really is such a thing as "ad blindness" and people will automatically skip over this compelling information.
7. Make a "first-time visitor" page. This is your opportunity to explain why you’re different from your competitors.
8. Update your copyright statements. Fix that 2003 copyright at the bottom of your pages because it makes you look outdated. Do this automatically in php with <?php echo date(‘Y’) ?>
9. Review text and copy, shorten where possible. Bold the most important actionable item on each page.

SEO AND TRAFFIC ANALYSIS

1. Get and use traffic analysis software. Google offers Urchin for free. With Urchin you can see where people go on, in what order they navigate, where they leave the site, and what content is least and most favorite. For example, the traffic pattern on one site was home page - pricing page - order page. 40% of all traffic bounced on our home page (they came and went without going anywhere else). During a site redesign we created navigation that reflected the browsing patterns of our clients. We used funnels in Urchin to determine where we were losing people in the order process. In order to increase conversion it is first important to know what your clients are doing before you try to influence them into purchases.
2. Also look at your statistics and locate the top landing pages...and work on them hard. Your index page might be great but if your other top landing pages do not appeal to customers they will leave. Check also the top exit pages and see why people are leaving your site.
3. Make sure you attract qualified traffic. Ex. – if you sell Mac software, don’t advertise that you sell Windows software just to get more traffic. This will drive more visitors with no intent to purchase and decrease your conversion rate.
4. Implement a "site search" functionality and make sure it’s accurate and record it. Not only will this allow users to find what they want, it will give you insight as to what they are shopping for and what terminology they are using so you can tailor your copy as necessary. This search data is good for a number of things. The two most important things it shows you is . .
5. What they want to find that you have. You react to it by increasing visibility and or usability.
6. What they want to find that you don't have. You react to it by adding new profitable product lines.
7. On every product page, make sure the exact name, model number, brand, type, etc. are in the <title>element. People who search with these keywords are READY TO BUY.
8. This concept is easily extended to other common searches as well. It's not a far stretch to do a bit of research to determine what keywords are used by your audience and then to develop landing pages for these keywords with the products right there and ready to be placed in a cart. I've seen this technique used and they went so far as to make each landing page a 1 step buying page. The visitor simply selected the products they wanted and provided their CC and shipping info. Once they clicked Submit the deal was done. That company increased their sales by more than 200%. The lesson they learned was to make the checkout process as quick and painless as possible.
9. Get good reviews from shopping authority sites (shopping.com, epinions.com, bizrate.com, etc)

PROMOTIONS / ALTERNATIVE IDEAS

1. Provide a "sale" or "clearance" section to attract the budget-conscious shoppers.
2. Offer a money-back policy if you can back it up. Few people will actually take you up on the offer (<1% in some cases).
3. Offer free shipping all though it might be better to reduce the cost of the item.
4. We have an upsale page that shows after the customer enters their personal data. The page is short and feature about 3-5 products at a reduced price (We first check to see if the products is in the basket and if its not we offer it) we present the normal price the saving and an "add to bag button"...products that work best are the ones that your customer are familiar with. By doing so we increased the average sale amount by 15%. Just make sure it’s a "take it or leave it" option. Put all the info of the products on that page otherwise you will force your client to look for that product in your website leaving its basket at a very crucial stage!
5. If you don’t sell an item, remove it from your site.   Better yet...if you've sold that item in the past, then recommend an alternative. Nothing's worse than a customer coming back to buy from you again and the product has just disappeared with no explanation.