arkansas, a buddy of mine and I used to do this game, also we wouldwrite down the guessed and the actual on our score sheet, that way we could find our problem areas and focus on them.

To make it even more interesting, take a wierd object such as a cup or whatever it may be and write on it with a magic marker something to the effect of "yardage judger of the universe" that gets passed to whomever wins that day. You would be surprised how much more you pay attention and take your time when something is on the line. I found that this helped me not just hap hazzardly guess, but make me take my time to think about it.

I shoot ALOT of tournaments and spend more than half my practice time judging yardage. Good luck!!!