For dull rigid body mechanics reasons (as the aircraft translates up it pitches down and vice versa) the smallest turbulence upset will normally be felt at the front of the aircraft getting worse as you move back.
Aha - this is something I hesitated to mention. I had a pretty good flight at the pointy end of a 757 on Thursday compared to a relatively poor flight at the rear of an A320 on Tuesday, and was wondering whether it was one of the reasons business class and first was nominally put at the front of the aircraft.
So for those of us paupers who don't normally travel in style, the best results can be seen at the front of the relevant section of cattle class, aligned with a liberal amount of praying to the gods of Bernoulli?