Don't forget the corners where your walls meet the ceiling (all the way across the wall, not just in the upper corners). If you don't have room in a standard corner, put your traps up high. The GIK traps work very nice.
Bass trap in a difficult corner
I have a corner that has very little space for a bass trap. On that wall is a large book end which I think makes for a decent diffuser but there is still a corner right next to the bookshelf that is completely exposed. On the adjacent corner is a trap. Will that be enough?