Have an Answer?
Figure out what you like about physicians and focus on doing that.
To be extra competitive, you could get a degree in a non biology field, and take pre-med classes (the biologies, genetics, chemistry, etc). Having some publications is usually good, they also want applicants with volunteer hours, experience with hospitals/doctors, extra curricular activities, and really high GPAs.
When you make up your mind if a doctor or Environmental is more interesting, ask again. In the mean time, Look at the book, "Occupational Outlook Handbook" available at all libraries