Music is a beautiful gift and one that lasts a lifetime.
My grandfather was a professional musician and I began lessons at age 5 and continued playing until I left for college. Today, I regret ever having stopped. Unfortunately this is a common refrain as many preteens and teens lose interest in activities, even those at which they excel.
As each child is an individual, I recommend speaking with your daughter in a non-confrontational way to get at the root of her perfunctory practicing.
Does she enjoy playing music? Maybe she has other appropriate interests she would prefer to pursue.
Would she like to try another instrument? Although musical instruments are an investment, her school may be able to give her loaners.
Ask her if she'd like to mix up the repertoire. Classical music is wonderful but a little jazz or popular music may help her find the joy in playing.
Perhaps she enjoys piano but just cannot find enough time for studies, music, and her other interests. Help her with time management skills.
If she is goal oriented, a recital or music camp admission may focus her efforts.
Or maybe she finds practicing solitary. She could form an ensemble with other kids her age. This way some of her practice is also social and the commitment to her band mates may provide peer motivation.
If the solution comes from her, she is more likely to find internal motivation to practice more often.
---
Candace Lindemann, Ed.M. - JustAsk Expert
Educational Consultant and Writer
http://CandaceLindemann.com