One of the things I learned from my Classical guitar teacher is the elbows are the key to hand position.
Show Image(http://www.meantone.com/MusicDownloads/ArlingShaeffer/pages/Incorrectguitarposition.jpg)
parallel to side of my keyboard
I just realized while I was playing a game that my mousing hand tilts in a little bit. Some times this causes inaccuracy when I need a quick up or down stroke. I am currently playing games with a logitech g5.
I imagine that ideally when I mouse my hand should be aligned to my forearm; parallel to side of my keyboard.