The most important tip I have is that you must love it, because there is alot of work involved! Even if you are not that great at math, you can still get by! A big choice in choosing a school is whether the astronomy department is separate or part of the physics department. I would still choose this major, as I love it, but it is really only worth it if you get a graduate degree. The pros are there is so much space to explore, that it will milenia before it's all discovered, and that is just out local area!
It is a very interesting topic and is very, very intuitive and hands on. I would recommend studying this major for anyone, it is a great major to put on your resume. They are all pros, there are not any cons that I could notice. Once again, this is the major for everyone!
This major is something of an add on. It's probably not a great career choice on it's own, but with all of the physics and math background that you'll take you would emerge well suited for further education in anything from buiness/finance to engineering. I would happily repeat my educational experience in astronomy physics because I learned the math I now need for financial analysis. I'd also repeat it simply because I love looking at the night sky and pondering all of the objects I can see there; my knowledge of the night sky has provided a lot of enjoyment in my life.
Astronomy is a very interesting major, but not very useful usnless you plan to go to graduate school. Most people entering the major do not realize that it is extremely math and physics intensive. You will have to complete calculus and differential equations, as well as take the same physics classes as physics majors. Many astronomy majors also end up double majoring (or at least minoring) in physics. If you love science, and learning about the universe, this major is for you. But it will likely not get you a job right out of college. Choose this major if you want to get a PhD in the long run, and either work as a professor at a university or do high level research. I would probably have chosen aeronautical engineering instead of astronomy to facilitate my job search after college.