I'm the least superstitious person around until about two weeks before I take the LSAT. Both times I lived complely by routine, every single day. I didn't wear underwear the first time I got 170+ while studying for this past June's test, so I haven't worn them since. I also had a really awful broken toenail when I started practicing, but I didn't want to alter anything so I refused to clip it after the test.
I know none of this actually helps, but the psychological reinforcement is comforting.