Winston has a great idea and I'd like to expand on that a bit.
Take out a sheet of paper for each webpage you think you want (Home page, Clients, Testimonials, Contact Us, etc.). Lay them out in the order you think you want them in on a space you can arrange them. Then jot down a brief outline of the content you think should go there, leaving room to fill in the blanks as you go.
I find that as you jot down more things, it triggers an idea for content that should be on another page. When you figure out what you want on the page, the content should fill itself in. This is a couple day project, and you might find yourself thinking about those sheets of paper at odd times, but it does help me sort my thoughts, and the content seems to flow from the organization.