If you take a (decent) class, you should spend 1 whole day doing man overboard drills. To do it yourself: Get a fender, extra life jacket, or other float, and drop it overboard. (Don't throw it.) Then practice going through the motions of getting the boat turned around, behind the float, pointed upwind and stopped next to the float. Do this again and again and again and again until you can literally do in your sleep. Then do it regularly. The American Sailing Associations book on sailing has pretty clear instructions of doing MOB turn (figure 8 really) and stop. Next best choice is to drop sails and motor over to them. Can you see them well enough to not hit them? If not, starting the motor may not be your best choice.
On the boats I usually sail - bigger boats - it is common to tie yourself to the boat with a harness and tether. Especially if your other crew is asleep. (What if you wake up and he is gone? How do you work back down your course? Hint you need to know what compass course has been steered) I always have jacklines out, I know where my harness and tether are, and I usually tie myself down. Of course I single hand a lot and no one is going to come back and get me.
People never go overboard in calm seas on sunny days. If they got hit with a boom - not an issue on the CS boats really - they are probably unconscious at least and likely hurt. A boat hook can snag a harness or a belt. You need some way to haul them aboard. Best to say in the boat if possible.