Document, document, document. Keep well organized records. Three ring binders work great. Don't go overboard on trying to computerize things. Use your computer for web searching, e-mailing, and creating documents and correspondence.
Medical doctors are very busy.
Saving them time and providing them information they will be needing in advance is much appreciated by them. This will allow your doctor the opportunity to preview your questions and find answers to your questions in advance. It will also put you in a position of directing your consultation the way you feel you want it to go. Call your lab or e-mail days in advance to cover all contingencies and questions. This will facilitate testing and will aid the lab because there will be no confusion or misunderstanding regarding the specific tests that are to be run.