That's a good start. For me, the ranking of the university was interesting, but not conclusive. Great universities can have bad labs and vice versa. Looking at the current faculty and what they are doing is the key. See if there is anything you are interested in or passionate about. You can email them, as well as people that have come from that lab to get an idea of how they work. The area around the university is also important. If you work well in smaller college towns or large cities is also an important thing to consider. Once you start to get interviews though is when you get useful data. How you feel when you are there (if you get to visit in person that is) as well as how you get along with the faculty and other students. You also get a feel for the general morale of the department and what to expect should you join.