Take your time. Make sure your visit is thorough. Even before I go visit the administration and ask for a tour, I'd just wander around the law school during classes. Maybe try to talk to some of the students, try to have some of your questions answered. If you can't find a single friendly student to answer SOME of your questions, then maybe that should be a red flag.
I would also concentrate on life BEYOND the school. Find out about housing. Check out some of the apts around campus. Go knock on some doors. Ask politely how it is, but especially ask about the noise level. Usually apts around campus are filled with undergrads (if you go to a law school attached to a mother institution). Find out if noise is a problem. Drive around the area, check out the housing. Check out the vacancy rates. Is there enough housing around the area? Are there vacancies? If you are going to have a car, drive around school during peak hours. Is there a lot of traffic? IS parking murder? These are things you should be looking for.
Back to school itself. Check out the atmosphere. Check out the library. Check if grades are posted outside (some will even show the median grades of the classes). Are the medians low? Are the curves murder? Maybe you thrive on cutthroat competition and this is ok with you. If not, this is something you should consider.
Again, take your time. I'd check into a hotel (hopefully around the area you plan on living, if you can figure it out.) I'd stay at least 2 nights, so you get ONE FULL DAY in the area you plan on being in. It might get pricey, but it's worth it to make a truly good decision. Check out the recreational life, are there things around that you would like doing?
Notice I focused a lot on you figuring out what life outside of school is like. This is personally very important to me, and this is why I would recommend it. Based on my undergrad experience, I realized where I live, commute times, neighbors, all these things directly effect my academic performance. Maybe you don't care about this. Maybe you can live in a roach-infested closet all alone doing nothing but studying for all three years. Then you should just focus more on the school...