Typically, you'll expect the following (which may not be too much different from pediatric examinations that you may have experienced as a child):
Measurement of height, weight, blood pressure, and heart rate (usually by a medical assistant).
Examination to look for visible problems and those noticeable by stethoscope. (You will have to undress for some or all of the examination.)
Questioning of medical history, family history, and medical problems.
Instruction on self examination for gender-specific cancers and other potential problems.
Additional instruction or counseling as appropriate (e.g. smokers are advised to stop smoking, overfat people are advised to lose body fat, everyone advised to eat healthy and exercise, etc.).
Vaccinations given if not up to date.
Blood sample to be checked for cholesterol and blood sugar levels, if not taken recently enough (depending on your age and the results of the previous test).
As you get older, additional tests may be specified.
If problems are noticed in the examination or from the blood sample, further testing, referral to a specialist, etc. may be recommended for a subsequent visit.
In preparation for the examination, do the following:
Do not eat for the 12 hours before the blood sample is drawn.
Review your medical history.
Make note of family history of diseases, particularly if they occurred much younger than typical, or an uncommon disease occurred to several family members.
Make note of any medications or class of medications that you are allergic to. If there are medications that close relatives are allergic to that you have not used, make note of those so that if a physician wants to prescribe one, you can warn him/her about it.
If you have not already selected a primary care physician, and have no other means of choosing one (e.g. friend or relative referral), it may be slightly advantageous to choose one of the same gender and about the same age or slightly older, due to being more likely to know about from personal experience some medical issues of your age and gender. Also, some medical groups' web sites give physician profiles; a primary care physician indicating interest in some topic that may be relevant to you may be advantageous.