Letters of recommendation:
In general, I am willing to write a letter of recommendation for anyone with whom I have had a substantial, positive mathematical interaction (e.g., you've been in one of my classes and we have spoken a good amount).
I do, however, have some guidelines and limitations for the letters I will write:
You need to submit a full request (defined below) to me at least a month in advance of your earliest deadline. That said, at least six weeks is strongly preferred, especially for letters involving significant mathematical content.
A full request constitutes:
A detailed description of the program, scholarship, job/company to which you are applying.
An explanation of your motivations for applying, and some understanding of your (possibly short-term) career goals.
An explanation of why I am the right person to write you a letter for this opportunity.
Your curriculum vitae or resumé.
The pronouns you would like me to use for you in any letter.
Any personal statements that you need to submit with the application (drafts are OK).
A list of all relevant deadlines.