A prospective customer and I were talking a few weeks ago and he asked how he could tweak his website to sell more online. He has a great looking site, stunning photgraphy, but there were a few mistakes being made that were costing sales.
1) Close the disconnect between the website and the webstore. On his website (and you see this on lots of sites) you click on 'Wine' on the main navigation, and see a list of the wine, read about the wine, but when the time comes to order the wine, you have to click 'store' on the main navigation, remember the title of the product and go purchase it in a seperate area on the site. It should be as simple as possible for someone to purchase from you. This means having the 'Add to Cart' button right there with the tasting notes, product photography, etc. Your wine page and your store should be one.
2) More details on the actual wine. There is no limit to the amount of information you can put on a website. A large part of the buying population are methodical people or humanistic type people who enjoy reading a lot of detail. This includes tasting notes, ratings and reviews, etc. More detail will see more wine.
3) No forced account on checkout. When a customer wants to checkout, they want to give you their credit card, not come up with a unique username and password to create an account. Forcing a person to create an account on checkout will result in lost sales.
4) Own the search for your own label. If I have a wine at a restuarant, at a friend's house or somewhere else, and now I go search Google for that product. That brand should come up number one on the search. Not coming up number one (or in this case not showing up at all) will cost sales.
5) Have an environment of monitoring and testing. Google analytics is free and pretty easy for a web developer or designer to setup. On the website in question I noticed that google analytics was running on part of the site, but not on the store part of the site. You really want to get a solid connection on analytics between your website, your store, blog, etc. Without strong analytics it's really hard to gauge the performance of a website.
And a few bonus ideas...
1) Provide assurances in the checkout. The right security assurance message will increase the number of people completing the checkout form.
2) Make sure the website on your current business cards is redirected to your live website. (Again this was specifically directed at this prospect, but if you're not building your own website, ensure that the domain on your marketing material is your domain)