Your personal physician may be able to provide you with what you will need or, at least, should be able to make a referral. Travel agents can also steer you in the right direction. There also are specialty clinics that can give you the most up to date information on what you will need based on your itinerary.
For our trip, Susan and I got, or are getting: Hepatitis A & B with boosters, Tetanus, Typhoid and we will take Malaria tablets enroute. The boys already have had the Hepatitis shots as part of their routine physical exams. The Typhoid immunity is available in capsule form and we opted for that method.
After this is all done, there is only one other kind of shot I plan on getting for a while...