I prefer to dry hop in a "bright" tank. Many commercial brewers will separate the beer from the yeast before dry hoping, I think sierra nevada dry hops in the fermenter. I have a separate keg that I add the hops to in a Stainless mesh bag, then purge with CO2 before racking from the fermenter into it. I let it sit for 3-4 days before transferring into serving kegs.
I think every one has their own method for dry hoping, but this is mine.