Remember that the definition of your target audience will guide most of the rest of the site's development. If your site will serve as a corporate intranet, you'll be less concerned with flashy graphics and dynamic elements than if your target audience is potential customers. From here on out, always keep the end users in mind and let them guide every decision you make. Whether your site is an intranet or an extranet, the end-user will benefit by your foresight and consideration of their needs and wants. Site maps are an invaluable tool of Web architects.
Every successful site starts with a blueprint of the site's architecture.
Start with your home page and branch down from there. Include subsections and sub-subsections. Don't leave anything out. If your site has multiple-screen order forms or sequential articles, maybe a strict numbered sequence is best for your site. Make sure that your site map mirrors whatever navigation strategy you choose - you will refer to it many times in the days and weeks to come.