Advice for writing a rec letter for myself from a professor's perspective?

I’m attempting to transfer schools and I need rec letters. One of the professors I asked told me to write a draft for him and we would revise it together.

I have no idea where to start though. I don’t know this professor very well (but better than my other professors).

Any have advice or good sample transfer rec letters?

That’s a very tough, if not inappropriate, thing to ask a student.

My suggestion would be to write a few bullet points of key themes with a few supporting examples for each, and review them before investing a lot of time in writing the full letter.

It also helps to share any themes you are using in your own application to help understand how the two align.