You read my mind! Here's one of my favorite caveats:
Plan your work, work your plan.
No one plans to fail, but too many people fail to plan.
Best time to get LOR's is after Jan. in the 10th, 11th, or even the 9th grade. At that time of year, teachers are no longer bombarded w/requests from desperate students. They'll have plenty of time to write a great LOR. Be sure to give them the name & address of the director of admissions at specific colleges you're applying to. Otherwise, they may address it, To whom it may concern; that's the same as, Dear Occupant, & we all know where that mail winds up!
I've had situations where the teacher asked the student to write something & they signed it, but that was only after I enhanced it and it went back to the teacher for their final approval & signature.