Reddit reviews The Practice Revolution: Getting great results from the six days between lessons

You can definitely learn your pieces faster. The problem is that you only have one way to practice - mere repetition with a metronome - whereas fast learners have countless ways of practicing.

This is normal though. Most students have no idea that there are many ways of practicing, and choosing the right ones can save you hours or days of practice time.

A great book detailing different practice techniques is Philip Johnston's The Practice Revolution.

Besides that, based on your comment, it seems you need to shorten your practice chunks. The brain learns faster with manageable chunks, and 8 measures seems too large a chunk for you right now.

These are more about practice techniques than lesson plans, but really good and aimed at young student: Practiceopedia: The Big Book of Practice Help


And from memory this one is more aimed at the teacher: The Practice Revolution: Getting great results from the six days between lessons

Let me suggest The Practice Revolution by Philip Johnston. It will likely cover most of the issues you'll be dealing with. It's written for teachers like you.