I usually cold crash the beer as soon as I keg the beer, then I'll immediately hook up the CO2 and let it force carb. If I'm in a hurry, I set the pressure to 50psi and shake the keg for a few minutes. It's the fastest way to get the beer carbonated. If I'm not in a hurry, I set it and forget it.
Using corn sugar is another viable method, however you can't cold crash and it takes longer. I just don't see any significant benefits to it.