Work hard in your lessons to get as much done as possible so you don't need to do anything at home. Do you find the motivation to study in college? I suggest you use your frees as much as possible to get things done. One teacher of mine told us that the more you get done in your frees the less you have to do at home. I probably do 2-3 hours of work in my frees over the course of a week, and half an hour each night. But I work quickly anyway, and what takes me 15mins probably takes some upwards of 45mins. You have to find out what works best for you.