Decide if summer school is right for you (see the Related eHows).
Find out if your academic-year school accepts credit from the schools you're considering.
Imagine your ideal scenario in terms of academics and location. Is there a program that has the classes you need and also looks like a fun place to spend a summer?
Think about what the school's location offers besides studying. Are outdoor activities important to you or do you prefer an urban environment?
Contact the admissions offices at various schools and ask if they can give you addresses of students who have attended summer school there. These students can be a great resource.
Visit with your school counselor for additional advice.