1. Use SSL only within your cart.
2. Don’t use SSIDs in your page URLs.
3. Use good validation.
4. Use friendly validation.
5. Cache everything you can.
6. Minimize database hits.
7. Use stored procedures.
8. Give your database and your website separate homes
9. Set up your database server to handle the kind o f read/write-heavy operations it’ll have to support.
10. Set up your web server to handle the kind of throughput- and cache-heavy operations it has to handle.
Read more: 24 E-commerce development tips | Internet Marketing Strategy: Conversation Marketing http://www.conversationmarketing.com/2010/02/24-e-commerce-development-tips.htm#ixzz0h38U90Xw