by Diana Davis
The short answer: Ask, and ask now!
The longer answer: If you want to have a teaching recommendation (or two or three) in hand by the time you are applying for a job, you should plan ahead. Each semester that you are teaching, ask a professor to sit in on your class. Most likely, there is a professor who is officially overseeing your teaching, so ask that person if he or she is willing to watch you teach and then write you a recommendation. The best thing is if they write the recommendation now, and then file it away for later use. Alternatively, they can just make some notes while they watch you, which they can use later when they write the letter. But the most important thing is to have someone observe you while you are teaching, so that you don’t have to scramble when you are ready to apply for teaching jobs.