I have never been to good at that last part, lol, much like you all I am always picking up more games a building a backlog. Mostly I just play as much as I can, try to prioritize games, and then wait for those lulls in between releases to get caught up. Fall time heading into the holidays is always tough as a lot of games are dropping, but summer usually slows down a bit I can get somewhat caught up.
I also tier my games, so "must buys" I puck up day 1 regardless of backlog. Then there are games I want to play but don't need right away, I will usually use gamefly for these as it is cheaper and spreads them out a bit for me, or I grab them on sale later. Then there are the "seems interesting but I'm not too pressed to play it," those end up at the end of the gamefly list and I get to them as I can.