You’ll likely need 2-3 letters of recommendation from your teachers. Ask the teachers who know you well. They’ll be able to provide real insight for the college admissions officer. Be sure to get the letters in on time. When you ask your teachers, make sure it’s a one-on-one conversation. Don’t ask when there’s a crowd around. Be sure to give the teacher plenty of time! Don’ t ask just before the letter is due, this makes it harder on the teacher.
Check out this article for more information.
http://u101.com/articles/get-accepted/recommendation-letters.shtml