Find an undergraduate school that can fulfill all your needs. A good school will have a strong base in the scientific fields such as chemistry, biology and physics, as well as a good general education in the area you choose to concentrate your studies.
Choose an adviser who is knowledgeable in your major field of study. Find someone in Arts and Sciences if you are majoring in that area. Find an adviser in the psychology department if you are focusing on a psychology major.
Pick an adviser who also has ties to the health field you wish to enter. There are many health-related fields, such as dentistry, optometry, physical therapy and pharmacy. Pick an adviser with a background in the area that you are most interested.
Be aware that an adviser can be changed if your intended major or health field changes. An adviser is there to help you get the most from your education. If you change your original direction , another adviser may be of more use to you. Your current adviser will be able to help you find someone more suited to your new path.
Concentrate on grades rather than prestige. Medical schools are competitive and you need excellent grades to make the cut. Choose a school that is good, but that you think you can do well at and make good grades. Johns Hopkins and MIT may be prestigious, but they are also tougher. It is better to get A's at a state school than B's at Harvard.