If you have planned ahead, you should be scheduled to go on a tour of the college. The tour will give you some basic information about the college but you can get much more from the tour. How? Talk with the tour guide.
Most students on a tour will not ask any questions of the tour guide. Some of those that do ask questions will ask stupid questions. Yes, you can ask a stupid question during a tour. How many students go here? What majors do you have? These are questions that anyone who has done any research will already know.
But you have prepared for your visit so you can ask good questions. Not sure what a good question is? Here is a list of possible questions you might consider while visiting a college.
After the college tour there will often be an informational session. These can often sound similar from college to college but you can ask questions of admissions counselors during the informational session so use this opportunity to get answers to more of your questions.
After the formal tour and informational session, wander around campus. Talk to students you see. Ask them questions. Look at areas where students have posted information about what is going on around campus. Do these sound like the sound of activities you would enjoy?
Visit the department of any potential major you are considering. See what sort of information the department has posted. Research opportunities? Graduate school options? This can tell you something about the focus of this department. If there is a professor in an office with an open door, introduce your self and see if they are willing to tell you something about the department.
Visit the library. Is it being used? If not, the school is probably not very academically focused. Are there adequate computer facilities in the library and around campus?
Eat in the cafeteria. Is the food good? It may sound like a trivial thing, but after 4 years of eating the same food, it will not sound so trivial. Also, while in the cafeteria, listen to what the students are talking about. Are they talking about what they were just discussing in class? Are they talking about the big game on Saturday? Are they talking about the big party Tuesday night? There discussions will give you more of a feel for what the college is like.
If you follow this advice, you will learn more about what the college is really like and will be in a great position to decide if this is a good college choice for you.