Since I don't know anything about your site or it's operation, here's a few general tips that worked for me.
1] Begin At The End -
Some call this the backwards forward principle, but the basic idea is to put yourself in your client's shoes starting from the end result. An ecommerce site would start with shipping. A service oriented site would start with a contract (or order).
This approach solves several issues at once. First, it allows you to ensure the site user will have the best possible experience. Nothing's more horrible to visit a flashy, fancy site and eventually reach the payoff (end) only to discover problems. This happens a lot and tells me the company is a little shaky. Many times it stops me from ordering.
Secondly, your site will be constructed in a more streamlined manner. If all your content is tailored toward the end result you'll find you've created a natural flow from beginning to end. No fluff, no leading your clients down a dark alley. Just a pure connect the dots flow, from A to B to C.
2] Keep It Simple -
You are very close to your project and know a zillion details you want to share. It's OK to make that information available for those willing to go the extra mile and do some homework. But most users want the simplified version.
Boil it all down to an elevator presentation and make that your sites primary focus. You may then offer more details via links for those who want to dig deeper.