Those who are bright and want to study. I seek racial diversity, but that is a big problem in the MPA program. We have gender balance, but we tend not to be racially as diverse as I would like. As an organized person - in my teaching and keeping track of developments in the class and seminar. Students' evaluations have generally been very positive.
Few students require contracts at the graduate level.
However, when I do work individually with a student, I look for clarity of vision of what the student wants to do. The faculty colleagues the students have worked with in the past, and how clearly developed is their focus for the contracts.