Letters of recommendation are not required for all universities. For instance, in California the UC system and the CSU system do not require letters of rec. However, many private schools do. For specific information, please visit the admissions page for the university (universities) of your interest. Note that sometimes the universities ask for the letters to come from very specific subject teachers. Also, note that your counselor will most likely also need to write a letter. See the timeline below.
TIMELINE
Ask letter writer for recommendation in person or via email 3-4 weeks before deadline
Give a resume or brag sheet
Pick up brag sheet in the counseling office or HERE 3 -4 weeks before deadline
Give writer a friendly reminder of due date 1 week before deadline
Follow up with letter writer to make sure there 3 days before deadline
are no problems or questions (if needed)
Send writer a Thank-You note via email or a physical card 1-2 weeks after deadline
Make sure to fill out the Brag Sheet completely and accurately or supply your resume with all information.