Compose a list of possible people to write you a letter. Don't be shy when asking for letters of recommendation. Teachers and guidance counselors are usually willing to help and likely have experience writing recommendation letters. Choose people who can vouch for you and know a little bit about your accomplishments and academic talents. Allow them enough advance notice to write the letter. An appropriate time frame is one month before the deadlines of the colleges to which you're applying.
Buy a book of stamps. You'll need them if you're applying to three or more schools. You'll need a stamp for each letter written. Supply your recommendation letter writers with an addressed and stamped envelope for each college you're applying to. You should find the mailing address for each college's recommendation letters on the schools' official website or in their admissions literature. Provide each person writing a letter of recommendation for you with a deadline by which the letter needs to be written and mailed.
Follow up with your recommendation letter writers a week before your first deadline to see how they're coming along. Check with each individual to see if each letter has been mailed to the appropriate school. Sometimes, the teacher or guidance counselor writing your letter may need more information from you. There are many other students also asking for letters of recommendation, most likely from the same teachers and guidance counselors, so don't expect your recommendation letter writer to know all the details of your life. It's common for them to ask additional questions after receiving your request to write the letter.
Send thank-you notes to everyone who provided you with a letter of recommendation and mailed them out. Let them know which colleges you were accepted to and which college you'll be attending.