Getting into medical school is difficult. It is a long, hard slog that will wear you down until you think nothing will ever go right for you, ever again — that is, until you get your acceptance! Here are some important details that can help you get into medical school.
First, and perhaps most obviously, is the most important question: Do you want to be a doctor? You need to be able to answer that question strongly and affirmatively if you ever want to have a hope for getting in. But once you have decided you want to become a doctor, there are a lot of things you need to do.
During your college experience, you need to check all of the (many) boxes to get into medical school. The academic environment of medical school is intense, so you need to show admissions committees that you can handle it. That means achieving a very strong GPA, as well as succeeding on the MCAT (Medical College Admissions Test). Typically, competitive applicants will have a GPA > 3.5 and an MCAT = 30. You will also need extensive coursework in the sciences. Typically, this means a year (at least) of: Biology, General Chemistry, Physics, Math and Humanities; Biochemistry, as well as upper-level science classes are also recommended.
But there is a lot more to medical school admissions than just grades and standardized scores. You also need extracurricular experiences that show you are committed not just to medicine, but to serving your peers and the less fortunate -— after all, medicine is about helping people. Typically, you need some mixture of the following: shadowing a physician (50+) hours, so that you know what being a doctor is like; clinical experience (often volunteering, ~150+ hours), so you know what a medical environment is like; non-clinical experience (often volunteering, too, ~150+ hours), so you can develop and show your altruism and commitment to humanity. Often, though not required (unless at major research universities), competitive applicants will have research (~100+ hours). This can be in any discipline — after all, not all doctors are purely scientists — but often clinical or hard science research is considered the most effective.
Once you have done all of these things, you should have a fairly competitive application. However, the process is not yet over. You need to fill out the AMCAS (American Medical College Application Service) application, which requires you to list all of your personal details as a student, person and applicant. This comes with a lengthy (and important) personal statement. You will also need letters of recommendation, typically from a mix of people (science and other professors, mentors, advisors, et al.). After you have submitted your primary application, you will often have to finish a secondary (school-specific) application with additional essay requirements. Then, if the admission committee likes what you have to offer, you will be offered an interview. Ace the interview, and then (more likely than not) you can get offered admission!
It's a long, hard path to medical school, but if you commit yourself the the process, you can achieve admission, and then continue on to a rewarding career as a physician. Good luck!