The July 11-17 issue of Times Higher Education includes a must-read article for the grad school bound. In "10 truths a PhD supervisor will never tell you" (11 July 2013) Tara
Prospective PhD students in history should think long and hard about who they want to work with. Ask around. Get to know something about the scholar you'd like to be your mentor. Has this individual shepherded other PhDs? Do his/her students land good jobs? What is your prospective mentor's publishing record like? Is he/she a good fit for your project? What will it be like to work with him/her? Will he/she lend a hand or remain aloof and passive reclusive?
Brabazon offers some dos and don't and, most of all, warns, "don't let the supervisors grind you down." Here's one of her particularly helpful pieces of advice:
The key predictor of a supervisor’s ability to guide a postgraduate to completion is a good record of having done so. Ensure that at least one member of your supervisory team is a very experienced supervisor. Anyone can be appointed to supervise. Very few have the ability, persistence, vision, respect and doggedness to move a diversity of students through the examination process. Ensure that the department and university you are considering assign supervisors on the basis of intellectual ability rather than available workload. Supervising students to completion is incredibly difficult.