Most male pattern baldness is on the top, back, or front of the head. A good stylist will help you decide the best cut to cover any baldness if that's your desire. For example, if you only have a small amount of thinning in the back, you can grow the top part of the hair just a little longer, and it will effectively cover it. This isn't to be confused with the comb-over, something most men should try to avoid these days. Frontal baldness requires an entirely different cut to help camouflage thinning hair.
When You Can't Cover Baldness
On the other hand, if the area is very large, hiding it may not be an option. It might be easier to go extremely short with a buzz cut and just let the bald spot show. While you may feel a little self-conscious at first, most other people will hardly even notice.