That and Trueachievements are instrumental in getting achievements if you're into that. My only problem with xbox360achie.org is I don't understand why they wipe the comments section away from individual achievements after some time has passed. The amount of options TA offers is awesome as well. Are you an achievement hunter? Personally, I enjoy reading the Road Maps prior to starting a game and then I'll make an Excel spreadsheet to organize it all (to avoid missables).
I am an achievements hunter, but recently. Starting last spring/summer really did I start actually putting effort into it. Usually, if it's a game that I plan on planning is not part of a series and is older I'll read the Road Map and get an idea of what to look/go for on first playthrough. I don't do multiplayer without doing story first and I try to not read much unless I have beaten the story. But some games, like Kane and Lynch, I'll look into before playing. Black Ops 2 I did research a bit as well, since I've given up on caring for COD sort of.
I haven't made an Excel sheet though, that's crazy haha. I do print out lists/maps sometimes for collectables.