[SFF]

Alligator,
The key thing for me to understand the power of OmniFocus was the simple phrase:
Plan in Projects, Work in Contexts

That means that when you are setting up new actions and projects, planning tasks, etc, you should be in the "Project" view. Then, when you are actually doing work (or deciding what to do next), you should be in the "Context" view. The Context view will show you all of the tasks assigned to that context--across all your projects--and can be sorted and displayed however you want. Sorting by due date makes a lot of sense, and it is how I usually work.

The implications of that are that when you add new tasks, you'll have to assign them to both a Project and a Context, and you'll have to give some thought to not only how you organize your Projects, but also how you organize and build your Contexts. There is a ton of information available in the forums on how people set up their Contexts if you need some help on that.