I think that there are two places to start.
One, as @ucbalumnus said, is to figure out your budget, run the NPC on all of the schools on your list, and see which are likely to be affordable. Most students need to restrict their choices considerably based on budget.
The other thing to do now is to start visiting schools. By visiting a few you can begin to get some sense of what you might want or not want, and this whole college search thing will begin to feel more real. You probably want to first visit schools that are relatively near where you live, if only because you don’t need to travel too far to do the visit before you narrow down what you are looking for. Also, when touring schools you can try to set up meetings with professors and/or get to sit in on a few classes.
What state are your from? I wouldn’t rule out your state schools too quickly. A lot of students want to go out of state because their in-state universities seem boring. However, in-state schools are often a much better deal and are usually very good for most students. Even if your in-state school is only a few minutes from your house, if you live on campus then it will feel like a completely different world compared to living at home with your parents.