If you applied in the Early Round of admissions (Early Decision or Early Action), you have probably heard back from your schools by now. If not, you should be hearing very soon.
What should you do if you were:
Congratulations! You did it. Enjoy the rest of senior year. You now know that you're going to college next year.
If you applied Early Decision, which is binding, it's time to rescind any other applications you may have already submitted. If you haven't submitted any other applications yet, then you're all set. No need to apply anywhere else. It's time to send your deposit to your ED school.
If you applied Early Action, which is non-binding, be happy that you have one or more schools in your back pocket. If you would attend your EA school(s) over any other schools that you haven't submitted yet, there's no reason to submit any more applications. Save the money. You still have a few months to make your final decision. Make sure you are able to afford your EA...