For beginner students it is better to practice a musical instrument 10-15 minutes every day, and not 1 hour all at once and only once a week. As you get better and better, extend it to 20 minutes, then 30 minutes, and try your best not to go more then 3 days without touching your instrument at all.
This simple concept works on any level: for professional musicians consistent 3-4 hours a day will provide much better results than 6-8 hours in one day with long breaks in-between. It can also put a lot of strain on your hands to practice a lot all of a sudden.
Try to get a little more consistent with your practicing, and you will find that you can learn your music faster than you ever expected!