I've just read the best post all year. It's on Psychotactics.com basically it gives straight forward advice which most marketers will run a mile from but for those who take it will be worth its weight in gold.
Here's the secret marketing 'trick' that'll guarantee to make you a fortune.
Speak to your customers
Let them tell you what works on your site, ask them abut new products and promotions. Do they think you're offering the best customer service. If they see problems do you react quickly to fix them or do you just brush it off as another annoying customer.
Reacting quickly and asking takes time and god forbid you have to speak to customers but in the end they are the ones spending cash, ignore them at your peril. Quite a few already have and they aren't around anymore (Woolworths anyone?)
Anyway Psychotactics put it in actual things to do, check out thier post.