When you consider teachers to ask to write you a letter of recommendation (LOR), please choose teachers in classes where you have shown growth, challenged yourself, or contributed substantially. Just because you were in a class does not mean the teacher can write you a SOLID letter of recommendation. Solid letters give SPECIFIC examples and have a plethera of vignettes to share. In some cases, "average" LOR's will not advance your chances and may, in fact, hurt you.
In general, I need a minimum of two weeks notice for LOR turnaround. I also require the following four items turned in at the time of your request:
1. Counselor Brag Sheet
2. Completed Typed Resume
3. Completed "Will you write me a letter?"
4. Copy of transcripts from Infinite Campus, counselor or registar.