What should I do on my visit? 

First, the information sessions, which are given by almost all colleges are the thing to attend. These are usually given by an admissions officer and give many facts about the college. The information session commonly either precedes or follows the campus tour. Duke University's information session was very helpful and the most informative of any sessions I have attended.

Second, take the campus tour. This is usually less informative than the information sessions, at least when measured by hard facts, but can provide many insights into the college, if you know what to look for. On the tour, walk close to the tour guide, usually a current student. Listen to what he or she has to say. Stuble nuances in the presentation can indicate a good or bad college. If the guide continuously speaks about how much fun the students have, this can be a tip off that the students at the college do not take the academics too seriously. For example, at a tour at Northwestern University, in Chicago, Illinois, a female tour guide constantly rambled about how much fun she had. (She had just graduated.) This can be the fault of a particular guide or it can indicate something about the college. The best way to find out if it is just the guide or the entire college, stop a few students after your tour while walking around on the campus. Ask them about the academics and the level of fun students have and judge for yourself. Most students are very willing to answer questions, for a few minutes anyhow. 

On the tour, ask the guide about any questions you may have. Almost every guide will give you building names and what is in the building. This information is useless to you if you are not a student. You will forget everything by the next week so don't bother to memorize the names. A campus map will work much better later after the tour to visit some campus locations than remembering the buildings anyhow. 

Most tours and information sessions begin in the Admissions Office. Before the tour you should be able to find many borchures on majors, classes, campus life, and scholarships. The general rule of thumb is when in doubt, take it. Take a brochure on every major you are considering in the least bit. This way you will have a reference back home and won't have to call the college later to obtain information. Take all brochures on scholarships, after all they cannot hurt, only help. Also obtain a listing of all classes available. This will commonly be a fairly sizeable book but is given free to visitors. This will come in handy when narrowing down which college to actually go to once acceptances have returned.