Hand in all your work on time. If you turn something in late, don't make any excuses unless they're legitimate.
Tell your teacher or professor as far ahead of time as possible if you can't meet a deadline or if you have to miss a class.
Consult with your teacher or professor whenever you're having difficulty with an assignment. The fact that you care, and that you're reaching out for help, means a lot.
Let your teacher or professor know if you think you've been treated unfairly. Standing up for yourself is something he or she will respect.
Exercise leadership in the classroom: keep an ear out for common ground when there are disagreements, and look for solutions that will satisfy everyone.
Ask questions, and lots of them. Teachers love an involved, interested student.
Challenge the teacher's or professor's views - gently - if you think there's something to challenge. This shows that you're engaged and interested in the material.