It's not clear in which sense you are twisting. Assuming you mean rotating the cue about its major axis...I appreciate the tips from everyone on how to find the proper position of the right hand. During the weekend, I used the mirror close to my table to just look at my right hand as I took a few practice strokes and notice that there was considerable twisting, on occassion. During my warm-up straight-ins, I would periodically do the same thing to see if it was twisting or not. Oddly enough, it wasn't apparent to me when there was twisting until I saw it in the mirror. Advice on this?
You can put a mark on the ferrule (perhaps on top of tape) to mark "up" on the shaft. You can then see easily if the cue is twisted during the shot.