When a customer does send you email, respond promptly, customers who have taken the time to send you email are like gold so treat them like one. Promote your site. Having a great web site is not enough, you also need to let the people know it. AltaVista, Excite, Web Crawler, InfoSeek, Lycos, Hotbot and Yahoo. Capitalize on a few keywords at first and then increase it.
Reciprocal links are also a good traffic booster.
If you have to place a link to your site, request that the other party link to you as well. Target banner ads are a big plus too. Capitalize on sales not on hits. Ordering online is quite an adventure for most of us and people love to tell such stories to their friends. They could be the most valuable free ad for you.