Research Health Advisories for any countries you plan to visit. The government can issue these advisories as can the CDC along with guidelines for you to pay close attention to. A Travel Medicine Physician can also advise you and immunize you if necessary.
You may need a letter from your physician if you have any hardware in your body or if you have had certain radiology procedures in the recent past that could cause problems with airport security.
Prescriptions should be kept in their original containers. Take a medical history and prescription medication list along with you. It should be kept along with your passport in a secure holder. You should also take along a copy of your eyeglass prescription just in case of losing or breaking a pair of glasses.
Travel protection insurance is always recommended as well. Some countries require proof of medical insurance when entering. These policies also cover a multitude of other things as well for example lost baggage, car rental, legal assistance, lost passport assistance and much more.
You have probably waited a long time and done lots of planning and dreaming about your vacation. Peace of mind is being prepared just in case you should need it! Bon Voyage!