1. Get the Official Tour
Even if the college you're visiting is just down the block, you'll still want to plan a visit to get a feel for campus life. Before you head out to any school, make sure you get in touch with the admissions office and let them know you're coming. This not only ensures that you can schedule an official tour, but it also demonstrates to them that you're interested in their institutions. Believe me, this is a sign-up list you'll want to be on, as colleges absolutely keep track of who has gone that extra mile (or extra thousand miles, depending on location) for an in-person visit.
Now, once you get to a campus for the first time, you may be a little overwhelmed, especially if it's a larger college. For this reason, I recommend starting with what the faculty wants to show you. It's a good way to get acclimated to the space and, more importantly, helps you figure out what they're not showing you. Are there any weird looking dorms that aren't part of the tour? Did they neglect to show you the gym facilities? Over the course of this tour, or tours if you're visiting more than one college on your trip, you're going to see a lot, so write down anything that gives you a strong reaction, lest you forget about it or conflate it with a different institution. Most importantly, write down any questions you have so you can get direct answers and ask follow-ups, and not necessarily just from your guides.
2. Get the Unofficial Tour
Don't get me wrong: The students or faculty who run campus tours are great. But their job is to show you what they feel are the best parts of the school. For this reason, it's also critical that you speak directly to your potential future classmates. Their answers can help expand upon what you've already seen in the brochures, website and official tour, and give you a better sense of what the college is like during special events and different seasons. This is why I strongly urge you to find ways to visit while the college is in session — you want to see the place at its busiest, and have the ability to ask as many students as possible any burning questions.
If you have the time, take advantage of any other official programs the school might offer visitors. You might be able to sit in on a lecture and get firsthand experience with how large classes can be, how active students may work, and how engaging professors can be. For a more complete experience, see if the school offers any opportunities to stay overnight or to shadow a current student. After all, it's one thing to know that a campus has a very active social scene, and another to be in the middle of it.
3. Get Your Own Tour
Talking to admissions officers and current students can only take you so far. Ultimately, this decision's going to be about your own comfort level, so make sure you get a real sense for the facilities that matter most to you. Sample the dining hall's cuisine, get lost in the library stacks, browse the free technology offered in computer pods, test the WiFi connections, and wander off the beaten path a little bit. Look at the flyers and bulletin boards and see what sorts of student-led activities are available; check out the student newspaper and get a sense for what's been going on in the vicinity. Could this place feel like a home for at least the next few years?
Oh, and don't forget to check out the neighborhood, too. Even the happiest of on-campus students often partake in local, off-campus activities, whether that's a rural area's hiking trails, a small town's local attractions, or the offerings of the adjacent metropolis. The littlest things, such as access to a bowling alley or a comic shop, can make the biggest difference to your overall happiness, so make sure you take it all in.
If you're looking to get a head-start on the questions you'd like to ask when on your college tour, you should check out our The Best 385 Colleges, which contains over 70 lists that can help you inform your decision, like Most Beautiful Campus.