Letters of recommendation from counselors, teachers, and outside people can add weight to your application. Some colleges ask for one teacher or counselor letter, others ask for two teacher letters and a counselor letter, and others don't specify an number.
If you have additional letters from another teacher or an outside person, such as a coach, an internship supervisor, an employer, or someone else, you can include these letters if you and your guidance counselor feel that they reveal something extra about you that is not obvious in your other letters.
Colleges don't appreciate receiving four or more letters of recommendation unless the letters add significant value to your application. If you have a letter from a senator or political candidate in whose office you volunteered, but you did not have an actual relationship with that person, the letter is usually not personal enough to add value to your application. After three or four recommendations, most letters become repetitive, so when in doubt, leave it out.
Many students struggle with deciding which teachers to ask for a recommendation. Just because you got an A in a teacher's class doesn't always make him the best choice. A teacher from a class in which you excel could be the right choice, but a better indicator of your college potential may come from a teacher who's class you struggled with — if you made an impression on the teacher with your persistence and motivation to improve.
If you've formed a bond with a teacher, that teacher can write more about you than a teacher who barely knows you, even if you did well in her class. If you're an active participant in a class, express interest in a subject, or regularly attend extra help sessions, a teacher can write a more detailed letter about you, which is what admissions counselors want to read.
College admissions counselors don't want to read generic letters. For instance, this sentence in a recommendation doesn't say much about your character: "Tim is a quiet and studious student who gets 100s on all my tests."
Compare the above example to this: "Tim is an intellectually curious student who stayed after class to engage me in conversation about a book he recently read for pleasure. He does not have the highest average in the class, but he does have a passion for learning, and his paper on the use of herbal medicines in Chinatown was carefully researched, well organized, and featured critical analyses of primary and secondary sources."
The second example is going to garner more interest from just about any college admissions counselor.
Once you decide who to ask to recommend you, think about when to ask them to do it. Ask teachers during your junior year (or earlier, if you have a reason) if they will write a letter of recommendation. Some teachers write letters over the summer, so make sure you ask them before the end of your junior year, and then remind them at the beginning of your senior year.
And remember, it's always a teacher's right to decline your offer if they don't feel they can write an effective letter for you. If a teacher hems and haws and doesn't say yes right away, it may be an indication that he or she is just not comfortable writing a letter for you. Many teachers do not want to hurt a student's feelings, so they write a lukewarm letter which does not really help your case. When you ask teachers, you could say, "Do you feel comfortable writing a letter of recommendation for me?" or "Do you think you can write a strong letter of recommendation for me?" If they say yes, that's great. If they hesitate or say no, then you probably should ask a different teacher.
The best letters are from teachers who know you well, who you have formed a good relationship with, and in whose class you have either performed fairly well or demonstrated interest. Guidance counselor letters are usually required — another good reason to get to know your counselor. A specific letter from a teacher, counselor, or outside person can enhance your college application and can demonstrate what type of student and person you are and your readiness for college.