I am happy to write letters of recommendation for:
(a) students who have worked conscientiously on a research project with me for at least one full semester,
(b) students who worked conscientiously on their Honors thesis or Peabody Scholar project with me, and produced a high-quality thesis or report, and/or
(c) students who earned a good grade in at least one of my classes, and preferably more than one class (“good grade” means at least a B+ in an undergrad course or A- in a grad course). However, you should also have made a mark in classes in a positive way, by participating where appropriate, coming to office hours, and otherwise leaving me with more information about you than your letter grade. What this means is that if you did not attend AND participate regularly in full class (beyond small groups) discussion or Q&A, please do not ask me for a letter, even if you earned a high grade.

Basically, the better I know you, the likelier I will support you with a letter and the stronger your letter will be. Every year I receive many requests for letters of recommendation, so please do everything in your power to make my job as easy as possible:

Make your initial request to me at least 3 weeks and preferably a month before the deadline. I will write letters only for students who waive their rights to read their letter. If you do not wish to do so, then please do not ask me to write a letter for you. Tell me clearly what you need the letter for (e.g., study abroad (at which University?), an internship program (in what organization and unit?), a graduate, fellowship, or job application (for what degree or program at what school or agency, etc.). The more information I have, the better I can tailor the letter to your needs. Get your materials to me as soon as you are able, at least two weeks before the deadline. Give me a list of due dates, websites of programs or schools, etc. Supply a statement of purpose (or an autobiographical statement, essay, etc.), your resume or vita (i.e., academic resume), and a copy of any of your best papers that you may have written that I reviewed or evaluated.

It is your responsibility to check with the school/program to make sure that your letters of recommendation have been received. You are welcome to send me a reminder notice close to the deadline. Typically, I complete my letters of recommendation close to the deadline. Keep me informed of your application process. If I am writing you a letter of recommendation, please let me know whether you received what you were hoping for.