Grab a copy of Your Pelvic Flaw by Mary O'Dwyer. Very well researched and it shows you how to do pelvic floors properly, and how to exercise in ways that do not increase abdominal pressure and put pressure on the pelvic floor.

Also a visit to a pelvic floor physiotherapist may be helpful.

I've always done 10 long squeezes (holding for as long as I can, ideally 10 seconds) followed by 10 quick squeezes
from what I can remember, more recent research out-dates this. I'll see if i can find out specifics - sorry I forget!