Sit on a hard chair; lean forward and tighten all your sphincter muscles, anal, vaginal, and urethral, in succession, front to back; hold the squeeze for one or two seconds; release, then contract from back to front.
If you are in a line-up at the store, you can squeeze all your PC muscles and lift up. You will notice that when you do this, you tuck in your tailbone and tighten your abdominal muscles at the same time. That's a good thing. Now, gradually release the muscles slowly, one by one.
Here's one they call The Flutter. You contract all the PC muscles quickly, and then release repeatedly.
Another one: Squeeze your PC muscles briefly for a count of five; hold; then squeeze harder, and hold for another five seconds; then squeeze as hard as possible and hold again for a count of five. Then, slowly reverse the process, releasing a little, holding for five, repeat, until your muscles relax completely.
As with any exercise program, start gradually. When your muscles begin to strengthen, increase the number of Kegels you do every day and the length of time you hold each contraction.
By making Kegel exercises part of your daily routine, you will improve urinary control (both women and men), as well as vaginal tone. In males, the additional blood-flow to the genitals due to exercising also helps with erections.