A good SAT Prep course can raise your scores as much as 150 points. If you have enough room to raise your score this much, you NEED to prepare. Strong essays and credentials will increase your chances for admission to a Selective School. Also you should perform well in the toughest classes available at your school. If you need answers about daily life, call the college's switchboard and ask for the student government offices.
College students are usually very willing to honestly discuss their campuses.
Another suggestion is to locate recent graduates of your high school who may be attending the college you are applying to and ask them for guidance. The summer before your senior year is a wonderful time to visit a college campus. At this point in your education, you will be excited about and ready to explore college campuses. My suggestion is to make a checklist and compare campuses and programs. Remember to examine the activities taking place outside of class.