Often it is not practical to use tripods in some areas (grandstands-train station).
Balance your body and, if possible, brace yourself against something solid, such as a wall or seat.
Then bring your elbows in firmly against your chest, and using the viewfinder hold your camera firmly against your head. Finally breathe, not too deep, and then hold it while you squeeze the shutter release.
Built in (good for 10 feet away, not good close up)
Higher end cameras
Electronic contact points
TTL metering: the camera measures the light in the scene based on the light coming through the lens. The camera is smart enough to meter the subject, do some quick calculations and then tell each (slave and master)(infrared) flash how bright they should fire.