In my opinion, one of the most important aspects of finding a college that fits you is feeling comfortable in the campus environment. Leaving the realm of high school and home life is a huge change, and being surrounded by people of all backgrounds and walks of life, along with an inevitably hefty work load will take some adjusting. With all of these new, exciting, but also daunting, experiences ahead of you, the last thing you need is to feel out of place or insecure. At some point, this will happen anyway, but I think it is very important to get a idea for what you may be expecting to live through at a certain university- a good way to do this is an overnight visit.
College tours only scrape the surface of what a school is about, to truly get a better understanding, you would have to live through a student. This will allow you to see their perspective on the social and academic scenes, and even to make a few friends so that if you do end up deciding on a particular school you will already have someone to talk to or grab dinner with.
When I first visited Hopkins in the winter of my junior year, I drove in through east Baltimore. Having grown up in a sheltered, nice area of New York, let me say it was a bit eye-opening to say the least. I took a tour, but was not too impressed, as the campus seemed bleak, with no students outside and snow covering the quads. I considered JHU as an option, but was not totally set on it until I participated in their spring open house program. I came back in early May, when the ice had long since defrosted, and all of the trees on campus were blossoming. During my stay, I met prospective students like myself, and got a more in depth impression of the campus itself and the typical day of a student. It was a great experience, and definitely drove me to ultimately make my decision of attending Hopkins. Once the program was finished, I stayed around a bit longer and explored the city of Baltimore with my family. Despite it getting a bad rap from people who have never visited, I found Baltimore to be an awesome place, with a lot to do and see. I find it important to have somewhere to go off campus to get away from sphere that is your university—both for physical and mental health. All in all, my experience was incredible and helped me confidently choose to attend.
If you are even slightly interested in a particular school, and have the time and means to explore it, definitely do as much as you can to feel out the institution—you may see a second or third tier choice become your dream school just from a visit.