Hey, my two cents...
You need to TRACK, TRACK, TRACK. You should know where your visitors are coming from, how long they are staying, what pages they visiting, etc. Install
Google.com/Analytics on your site or use
GetClicky.com. Next, install
http://crazyegg.com/ on your site so you know the behavior of your website visitors. You can make adjustments to your website designs.
You should also install Google's Website Optimizer tool and A/B split test every page on your site to see what converts better. The only way to improve your site's conversion is to test, adjust, and test again. It's a never-ending cycle, but the bump in conversions will be worth the effort.
Then, you need to understand your visitors, I assuming you've done some market research and surveyed your market so you know what emotions drive them and what BENEFITS they are looking for in a solution to their problem. Once you know this, you can create a compelling headline on the page that will catch your visitors attention, preferable with an image that will grab their attention as well.
Have a clear call to action on every page of your website, whether it is to order something right away or call a specific number. Have an opt-in form on the right of the webpage, so that you can capture your visitors information. Bribe them with a free report, coupon, discount, free item, etc. to give you their name and e-mail. The idea is now you will be able to follow-up with them in case you don't make the sale right away.
I hope this helps! Goodluck.