Well, I guess the best thing you can do is try to understand exactly what your situation is. For tuition, it's good to think about what you think is reasonable. Is going to a school that you have to pay 80,000 USD a year to attend worth it? Will your student debt be so overwhelming that you won't be able to pay it back post-grad? If you're nervous that may be the case, it's better to look at cheaper schools.If you're rollin' in the Benjamins then cost may not be as big of a deal.
For atmosphere, there are several different types of schools. You've got your huge universities, small liberal arts schools, and whatever's in between. All of them have different characteristics that may or may not appeal to you. The best way to figure out what's the best fit for you is to physically visit a lot of different campuses.
Deciding on a major depends solely on you and your interests. Some questions to consider: what classes in high school interested you the most? What do you like to do in your spare time? It may help you to talk to an advisor; sometimes they're helpful in figuring out what might be a good fit.
Choosing a major isn't always straight forward, and that's okay. Trust me, I've been there. I've switched my major twice. Luckily this third one turned out to be a good fit, but for awhile there I was beginning to lose hope XD
Try not to worry too much about it right now, you have plenty of time over the first few semesters to figure out what you want to do.