Start investigating all aspects of the medical school. There are hundreds of helpful websites with data, advice and insight. Before you register for your first year of college, meet with an advisor and create a long term plan that covers all the academic requirements for medical school admissions.
Choose a college major of pre-med or a basic science (chemistry, physics, biology, for example). Being a psychology or engineering major does not preclude medical school admission, but you are required to take the core courses of a pre-med or basic science degree.
Commit to your studies. If you haven't established good study habits, start now. Check with your advisor for information about programs for freshman on study habits and organization skills.
Manage your time well. Consider volunteer work, assisting in research or shadowing a physician. Medical schools prefer accomplished, balanced students.
Arrange to sit for the Medical College Admission Test (MCAT) late in your junior year. The test is on several dates in many locations around the U.S. and Canada.