Don't spell anything wrong. Be extra careful to make sure you have the correct spelling of the person you're addressing your application to. You can be guaranteed that your application will go in the trash if you misspell the recruiter's name or the company's name. Applying to lots of papers means lots of rejections letters. Don't let it get to you.
All good journalists have a huge file of rejections letters.
There's lots of papers out there, and chances are at least one will want you. If you're not involved in one of these groups now, you should be. Get as much experience as you possibly can, and do it early in college. Never turn down a story, even if you think it's trivial. Your editors will fondly remember you if you're willing to do any assignment they give you.