First, let me acknowledge that visiting colleges is a privileged activity: my parents didn't know to do it and neither did most of my immigrant-based high school class. I was told to apply to all the good schools, and then, if we got lucky, we could visit which ones I got into. Besides the obvious cost, there's an education factor. For some, it's an obvious fact of the application process. For others, ahem most people outside of the private school bubble, campus visits before getting in just don't make sense.
1) DON'T ASK QUESTIONS YOU CAN FIND ANSWERS TO ONLINE
If your question can be answered with a quick Google search, you're doing it wrong. I completely understand how overwhelming the college application process is and get that families will schedule a frenetic back-to-back tour schedule, (another no-no, see #2), but this is just a waste of your time. Asking if this college has fraternities or a journalism major is such a forehead smacker. This is your unique opportunity to get answers that could help narrow your stressful college search - why would you waste it on such an easy question?
2) DON'T SCHEDULE BACK-TO-BACK TOURS
Because there are so many options and so few vacation days, I understand the impulse to pack in multiple visits each day. But unfortunately that robs you of the ability to actually spend enough time on campus to determine if it's really for you or not. For some students, it's love (or hate) at first sight. But most are going to need more than an hour-long tour and info session to know if this is the right fit for the next four years of their life. The best experience will include a full day where you can go off the beaten path, try out the local student haunts, visit the library, and even sit in on a class if possible.
3) DO TRY TO VISIT DURING ACTIVE SCHOOL DAYS
I know scheduling this can be tricky, but the best time to visit would be during the school year when class is still in session so you get the full view of what it's like to go to college there. If you go during a college's break, you run the risk of seeing a ghost town or a summer school set that isn't reflective of the actual student body you'll be interacting with during the year. Try going during a break you have off that the college doesn't (pro tip: the spring breaks don't usually align, so that's a great time to go).
4) DON'T FORGET TO DO YOUR RESEARCH
You know to study the college's website and get a feel for the school's majors, clubs, and student life. But always go beyond that. Remember that this process is just as much a test for them as it is for you - when push comes to shove, you have to be 100% sure you're ready to spend four years of your life there. Asking the deeper questions will ensure you know what you're getting. Read up on the college's latest news - did they just unveil a new major academic focus or campus perk? Those are good ways of helping you narrow your search and find the right fit!