If the instructor poses a question to the class try to answer it, even if you are not sure if you are correct. One secret to college success is making sure the professor knows who you are. Answering a question, now and then, or asking one of your own will go a long way toward that goal. So make sure the instructor knows you are breathing. If your instructor writes something on the board, write it down.
Blackboards are treasure chests of exam material.
Be sure to write down every item your instructor writes on the board. You might not understand the point the instructor was trying to make. You might have even missed what he was saying. Write it down anyway. The material on the board is, in most cases, what the professor considers to be important.