RE: Judging Yardage?
Step off your yardage. When you hunt you will use the sames steps to judge distance. Many hunters will step off the area they hunt and leave landmarks at certain distances. It may be a tree, or a bush. Some have even put out rocks painted white..
But the more you practice the better you will get judging your distance. To practice this skill, I will use several targets in a field and walk at random. I then turn a spot my target and shoot estimating the distance. It's a fun game, and will certainly increase your distance judging ability. Range finders are good, but if you spot and stalk, the time it takes to use your range finder and taking a shot may be the difference between the one on the wall or the one that got away. Sharpend every skill you will use in the field.