There are lots of little tricks and visualizations when lifting. Here are ones I've used (or heard about):
1. "Toes up" during squatting credit to Sully.
2. When doing single bend over db rows, I pretend I'm trying to put that dumb bell into my pocket.
3. I read in one of Arnold's books that he'd pretend he was "hugging a tree" during db fly's.
4. Allen Cress made a comment a while back about employing a pumping motion with no rest at the top, which seems to be helping me on bench.
I'm curious to hear about other analogies/visualizations people feel help them.