This can be summed up in three easy steps.
Step 1) Do not ask a teacher (after not speaking to them for a year) for a letter. They won’t remember you or want to write a letter for a student who simply hasn’t interacted with them. Ask a teacher who you know likes and approves of you.
Step 2) Ask in person, if possible. The best way to ask for something is in person. Approach them after class or schedule a meeting with them to discuss the letter. Ask nicely.
Step 3) Don’t ask them a week before the letter is due. TRY and ask them at least 1-2 months in advance. Teachers have busy lives and need time to write you a good letter.
Step 4) Send them your resume as well as some key points you’d like them to highlight (Writing, Leadership, etc.) This will help guide the teacher in their writing process.
Step 5) Tell the teacher THANK YOU after they are done.