Depending on age, skill range, and desired rate of advancement, students should practice 10-60 minutes per day, 5+ days a week. Practicing helps students progress and is critical to developing self-confidence in their musical abilities. Daily practice is far more effective than long cram-sessions, so schedule a distraction-free time to practice every day. Your skills will soar, and you will enjoy making music.
The most ineffective practice goes like this: students look at their assignment, open their books, fumble through a piece from the start to the end, then close their books and walk away. A much more effective (and fun!) way to practice would be to start with a brief warm-up. Next, re-read practice directions and assignments. While working on individual pieces, implement a host of practicing strategies, such as practicing hands separately, counting and tapping or clapping rhythms, isolate a couple of problematic measures and just work on those, set a timer and only work for 5-10 minutes before moving to something new, or build in rewards. By varying the way you practice, you will enjoy your practice sessions a lot more.
Students who practice learn faster and retain information better. More importantly, learning the life skill of practicing will help you discover how you learn. Your body will be strengthened, your mind will be sharpened, and even if you choose to leave music in the future, the benefits of practicing will stick with you forever.
Remember to have fun every day!