There are many organizations offer MCAT Preparation Courses, but note that these are expensive. Many medical schools require applicants to submit an autobiographical statement or other written essay. Be sure to understand what is being asked and answer in the allotted space. Leave a copy of your resume too. Get to know professors early in your university years, so that they can incorporate information about you that reveals your character and personality.
Some medical schools focus more on academic factors and others focus on non-academic factors.
But all admission committees are looking for well rounded candidates. Get involved in activities early and take leadership positions in them. Almost all medical schools require an admissions interview. The key to a successul interview is preparation, preparartion and more preparation. You must know yourself, your values, motivations, skills and experiences.