To apply and to sign up for colleges in America is an intense and stressful process, to say the least. What makes it easy is making plans and researching ahead of time. It all depends on how high you set your sights of your dream college, because getting admission into a US college could be easy or difficult.
Know and understand the fact that there are more than 4000 degree-granting colleges in America, so basically, everyone has a college for their needs. And most of these colleges accept nearly all of the applications sent to them. The elite handful like Harvard, Stanford, Duke etc. accept only those applicants who they find are best suited for their institutions.
Since these elite colleges receives thousands of applications every year, their selection process is hard to pass through. That is why you need to do your homework, know your credentials, your strengths and weaknesses before applying there for admission.
You should start preparing yourself for college from your junior year. Finish off any pending obligations like special classes you need to complete for applying to certain colleges.
You can also check online at collegeboard.com to compare the GSA and the test scores of the students there with your own, and know how hard your competition is and what you need to do to beat it.