From the Perspectives menu, choose Review (there’s also a corresponding button you can add to your toolbar, if you like). In this view, your remaining projects are grouped in order of when they’re due to be reviewed.
For each project in the Review Today group (or earlier groups), check whether the project is in the state it needs to be in: Should you revise its actions, or add new ones? Should you put it on hold, drop it, or complete it? Or is it just fine?
Once you’re satisfied with the state of the project, select it and click the Mark Reviewed toolbar button or choose Mark Reviewed from the Edit menu. The project’s next review date moves forward and you can go on to review another project.