- Re-read and revise your studio policy - time off from teaching is the perfect time to do this yearly task
Organize tax records - get your receipts together and deductions categorized - don't forget deductions like bad debts from non-payers, lost or damaged music and learning materials and other studio business-related items that you have purchased
Think carefully about what you've been doing and what, if any, changes you might want to make for the new year
Sit down and write out your goals for the coming year (kind of like resolutions, but these are ones you'll work hard to keep!)
Look at your teaching schedule to determine if you want to change it and, if so, how. Just make sure you build in some "self-time".
If you use a computer in the studio to supplement lessons, take any new software for a test run before you show it to students
Take care of any piano maintenance that may be needed
Go over your studio's books or meet with your accountant to do same
I'm sure this list isn't complete, but I hope it will encourage others to add some additional items that should be done end-of-year.