Cover letter for professor to write LoR

[randomcat]

I approached a professor for a LoR, and I gave him my resume and transcript. He also requested a cover letter from me so that he knows why I want to go to grad school and I'm guessing just to know more about me. He mentioned that the more information, the better. So I'm wondering, what should I include in the cover letter? And how are these usually structured? So I'm thinking of including why I intend to attend grad school as well as highlighting some experiences from my resume. Is this ok?

[fuzzylogician]

I'd write down anything you might want him to include in his letter. Help him make the letter stronger. So: 

- How long he has known you and in what capacity

- What your specialization is, why you want to go to grad school

- What your background is, how it prepares you for grad school in your chosen (sub)field

- Anything important in your background: awards, publications, conferences, etc.

- Specific examples of anything relevant that he could/should know about you: details of the paper(s) you wrote for his class, details of how you organized something or other, details of how you came up with a new way to solve whatever problem in a lab meeting, collaborations you were involved in, how you helped tutor other students who were struggling, anything at all that shows initiative or otherwise reflects well on you. The key is in the details. The more, the better.