Dress like a student (not like an athlete, rap star, rock musician, or surfer).
Show respect and enthusiasm to your instructors.
Listen, listen, listen--you can't learn while talking to your peers during class.
Pay attention--don't doodle, doze, or daydream.
Try to contribute once per class period, with a question or contribution to discussion. Participation counts--and helps.
Have clearly marked notebooks, with separate sections--or separate notebooks--for each class.
Use a dictionary. This will increase your vocabulary and teach you correct spelling.
Have a partner/"buddy" system for studying. Have parents, friends, dormmates, etc. quiz you. Form study groups.
Read, read, read. Read magazines, the newspaper, sports books, science fiction, anything you can get your hands on.
Set aside at least three hours a day, six days a week, to study.
Get some of your homework done during school. Use free periods, extra time between classes, and the time before sports.
Sacrifice and work during times when you know other people aren't working. Work on a Friday night or Saturday afternoon. It will be worth it.
Volunteer for extra credit.
Get involved in extracurricular activities. Don't merely attend classes and go to practice. Join the Government Club or Cultural Awareness Organization, write for the student newspaper, give tours, etc. Get involved.
Work hard and be proud that you are working hard and learning. Realize that education is a key ingredient to many great things that you will accomplish in life.