Don’t fall in love with a school before you get in, and don’t apply to schools you know you can’t afford.
I’ve been around CC long enough now, and have a kid in college and a senior in high school. I can’t limit myself to just one single piece of advice, but I can certainly think of a few that are, IMO, the most important. (Affordability kind of goes without saying. You can’t go if you can’t pay for it. There is no magic money tree, so run NPCs.)
- If you care at all about what college you can get into, keep your grades as high as you can, without becoming grey-haired at an early age, or sacrificing your social life. Deciding you want to work hard in senior year is better late than never, but I also feel very strongly that kids need balance. If trying too hard in school is causing anxiety or preventing you from having any fun, reduce the work load by taking less stressful classes. The majority of colleges prioritize grades over test scores.
- Agree with everyone else. Forget the dream school. Your focus should be on match and safety schools. Be realistic, and do your research. Don't be one of those people that is flabbergasted that they only got into one, or worse, no schools.
- Be a nice person, and be involved in what interests you. Colleges want to admit people they like. Your teacher recs are important and being a good person will be reflected in your recs and your essay. Students shouldn't try to pretend to be someone they aren't.
If you want to read a very informative thread full of advice, try this one: http://talk.qa.collegeconfidential.com/parents-forum/1878059-truthful-advice-about-getting-into-top-colleges-for-your-average-excellent-student-p1.html