Kes
I'll Decide ...
This. ^ ^ ^The key thing is to remember that you aren't there to watch the game. It can be so easy to watch the game as it is in your non-active half, but then suddenly the ball is hammered clear and you are 10 yards off your offside line and in a world of trouble. The way it was told to me is that 80% of your focus should be on what is in front of you, you can keep glancing left to get a glimpse of the play but the focus must be immediately in front of you.
Assuming you're generally facing the field of play ie. "crabbing" which by definition suggests your main focus is always on the defensive line, concentration is the most important element of being a good AR.
When looking onto the field and doing this myself, I'm literally: Step, step - where's the ball? Step, step - where's the ball?
Difficult to maintain for a whole 90 mins I know but that's your job.
Works for me....