Beyond the Articles and Files (Documents and Gallery) Modules we've created within the site, you may want to look at adding some others. Many CMS sites will offer options such as Forums, Messaging, and Videos. These are all ideas you may want to incorporate within your site. For these, or any others you may think of, it's just a matter of following the same patterns we've been using throughout this site.
Start with planning out your Module. It's crucial to know how you want it to work before you start off, or you may find yourself rewriting large pieces of code (and I'm sure that no one really wants to do that). Once you have your concepts all laid out, start by creating the individual pieces. If you need some new tables in your database, get those created first.
Next, you'll want to take the time and get your DAL all "wired up" using the Typed Dataset option, as we did with the Articles module, or you may want to use the Object-based system like we did with the SiteSettings...