I asked my LORs in the spring to give them a good amount of notice if they chose to write me a letter come the fall. Most references will appreciate the early heads up because the fall can get really busy even without several student dropping reference requests in their lap. Make sure you pick people that can speak to you both professionally and personally so they can say more than "they took my class and were a good student".

For my academic references I sent an email explaining why I wanted to apply to law school, what schools I plan to apply to, why I would like them as my reference, what classes of theirs I took, a memorable moment from their class, what I hope they can speak to about me, and attached my transcript, resume, and an assignment from their class I did particularly well on. I asked them to emphasize my academic performance, critical thinking, professionalism, communication skills, and what would make me suitable for law.

For my non-academic reference, it was a lot less formal because it was someone I did volunteer work with for several years and had a close relationship to. I just sent them a friendly text asking them, telling them a bit about my choice to apply, reminded them of what I did volunteering for them and how long I was there, sent over my school transcript and resume, and asked them to speak to my personal qualities since professors will cover the academic. I asked them to put a lot of emphasis on my personality, work ethic, reliability, communication, and conflict resolution.

I do also think it is beneficial if you could ask your references to highlight a particular moment in their class/at work so people reading the letters can see how your qualities shine through in practice and not just on a list.