Some schools run special programs, and it might be interesting to keep an eye out for them.
Downstate for example, used to offer a special focus on Early Intervention for students (they still trained a majority of general practitioners, just offered special electives to like 10 of their students). The program ran out (it was a grant) but there may be similar programs at other universities.
Look at the curriculums (most schools have it posted on their website) and look to see if they offer anything that looks unusual (Columbia has a major focus on mental health) as these will be the classes you take in grad school.
Lastly, ask around. If a university is known for something, people will know about it.
Do you have a specific specialty in mind? Or are you just trying to avoid an overly specialized school?