Disciplining yourself to study while at home can be a big challenge. If you can't learn to shut out spending time with friends or doing other entertaining things, it can be hard to devote enough time to a class. At the first of a term you should sit down and make yourself a schedule to follow throughout the whole course. This will help you to stay on track and get the most out of the money you put into education.
If you aren't focused on the material, you are wasting your time as well as other students’ time. Avoid using classes as a time to socialize. Situate yourself in a classroom so you don't have distractions.
Learning from lecture style classes requires a good ability to retain a lot of information very quickly. I found that taking shorthand notes instead of writing very word my teacher said was more efficient.
Sitting down and scheduling yourself time will help to give yourself a lot of stability. If you have a schedule it will be easier to stick to your habits when distractions start popping up.
Many students get intimidated by teachers and withhold questions. Be confident and realize that teachers are there for you, and they want to help you succeed. Ask all the questions that occur to you.