Try picking just one thing you've mastered, play through that, then move on to whatever you're working on or learning. Then pick something different that you have mastered on the following day.

Don't worry about the risk of forgetting something, because the chances are you'll be covering the same things at a higher level later on. Definitely don't worry about forgetting the beginner songs or practice tunes, as they are all at an introductory level that you should move on from when ready.