Letters of recommendation may touch on the following points of potential interest to graduate admissions committees:
How good are your research skills (of great interest to most graduate programs)?
Do you offer thoughtful contributions to class discussions?
Do you have good interpersonal skills that enable you to get along with faculty and other students?
Do you exhibit strong leadership skills?
Have you contributed to the various extracurricular activities of the Department such as Psi Chi and the Psychology Club?