When I don't have anything else that I feel like doing, I pick a random zone. I put up PF for an Atma group and run FATEs until it expires. If I get one, I move on to another zone. If I don't and PF expires, I move on to something else - I give it at most an hour of my time. In the larger zones where moving around is a pain in the ass, I pick a FATE that spawns often (like a CT unlocking FATE or one that is part of a Beast Tribe quest) and camp out there for that timeframe. I understand there is RNG to it, but I have been quite successful with this method and not stressed about it like some people are. Don't let it get the best of you - it isn't meant to be done in one setting.