Now, as a teacher, I try to structure lessons as a template for what should happen when the student practices at home. I think of practice as having three main areas:
- love of playing
- technical practice
- pieces
Second is technical practice. This is different for every student. If a student is preparing for an exam then technical requirement are very clear-cut. The motivation for practice is also clear. For a diploma level or university student there are two main aspects to consider. One is to keep up stamina and maintain facility in all registers so that you are ready for the pieces you want to play. The other is to identify and work on tricky spots in pieces. Looking at these weak areas shows us what techniques need work; slurred octaves? double tonguing? Find studies for these particular issues. Technical practice can be endless but I recommend limiting it to no more that a third of your practice time. You will become more efficient at achieving technical goals if time is limited!
Third is pieces. Don't try to do everything every day. If a student is working on four pieces then I would usually work on two of them in one lesson and the other two in the next lesson. So in in the students' practice time I recommend doing two different pieces per day, spending about a third of the practice time on each piece.
I also find it useful to go into practice with mini-plans e.g. "today I'll spend 5 minutes on whole tone scales", or "today I want to work on getting a clearer staccato in the last movement". If you start practicing with your priorities already worked out you will practice more efficiently. Of course some priorities arrive like lightbulb moments in the middle of practice. If that happens 'save that thought'. After all, the aim of having lessons is that the student understands the process and eventually becomes their own teacher.