It varies from institution to institution, but a few ways that high schoolers are able to contribute to their dream of finishing college faster is by taking International Baccalaureate (IB), dual enrollment or advanced placement (AP) classes. AP classes allow you to take college-level coursework at your high school. If you score at a certain level on the AP exam, most colleges will accept that test for course credit. In addition, those enrolled in IB classes may be able to earn college credit when they pass their final exams.
If you have a lot of experience in a certain subject area and have already mastered the content that is shared in the college-level course, you may be able to take a test such as the CLEP or the DSST and earn college credit. While you usually have to pay for these tests, they do help you finish college faster by giving you credit for information that you already know.