It sounds like you’re making some wise choices. If you’re not excited about any of the colleges that admitted you, it makes sense to take time off from school and consider other options.
When you are ready to apply to colleges, you would do so very much the same way you did the last time around … using your high school GPA, test scores, recommendations, etc.
However, you should definitely explain why you took the gap year and what you did during your months away from the classroom. You can use your primary application essay to do this or you can write a supplemental letter or essay, if you prefer.
You may also want to ask someone who met you during your gap year (e.g., an employer) to write an extra recommendation for you. In addition, you can retake standardized tests if you wish, but it definitely isn’t required.
Although most gap-year activities–unless they’re extraordinary–won’t do much to help an applicant to get into a college that he or she wasn’t qualified to attend straight from high school, admission officials do appreciate the fact that “gappers” are often more focused and mature than students who enroll right after 12th grade. So your gap year mighthelp to give you at least a tiny boost when you apply to new colleges next fall.
However, if you think that you MAY want to start college in September after all, you can call the colleges that already admitted you to see if any of them still have a space for you. Although the reply deadline has passed, if these colleges are accepting any wait-listed applicants this month, they might consider giving a spot to you as well. Similarly, if during your gap year you realize that you want to attend one of the schools that already accepted you, you should contact the admission office there to see what your next steps should be. You may not have to submit a whole new application. Some colleges may tell you that just an update will be fine. Your acceptance at these places won’t be guaranteed, but your odds should be good.
Good luck, whatever you decide.