Nancy Hamp gave you some great advice. I want to reinforce the importance of finding the right fit for you. So once you've studied the rankings of the Ivy Leagues, look at the size of the student body, and the type of student it most likely attracts. For example, Brown has an open curriculum -- basically you design your major. It tends to attract creative student or those with unique talents or interests.
Visit the campus if you are able, read as much as you can about each school, and try to picture yourself there. Ask around and try to talk to anyone that is currently attending to get a better sense of the school.
These schools are expensive, so if you need financial aid, look at what each has to offer. The good news about the Ivy schools is that they have big endowments so are often able to provide better packages than smaller prestigious colleges with smaller endowments. When it comes to need blind admissions, the Ivies are most able to keep that promise.
These schools are highly selective. If you are lucky enough to get in, take advantage of all each has to offer. You will have a network that will last a lifetime -- and each can provide a rich learning environment while your there. They can be intimidating -- but don't let that shake you. Anyone who has attended knows these are challenging. At first you may feel as though you may have been admitted by accident -- but that is normal. Once you get your bearings -- you will be all set.
And have a plan B for in case you do not get in to an Ivy. Look at schools that are a tier or two down but that have what you are looking for. There are plenty of great schools. Be selective in planning alternatives and apply to a number of them so that you end up with some viable choices -- any one of which that will work for you.
Best of luck.