And when I teach baseball umpiring clinics, one of the cardinal rules that I teach:
Know what the rule MEANS, not what the rule SAYS.
Some of that comes with time and experience, which goes back to getting game experience.
I was assigning umpires for a travel ball league. I had a double header one day that I was going to work, but I was short umpires. I brought up a guy from that did Little League games that had shown promise. We are in game 2, he has the plate. It is a misty, miserable day, and the home team is killing the visitors. We aren't yet to the run rule, but we are on our way. Ball hit to the shortstop, who bobbles it and can't make the play. Shortstop throws the ball back to the visiting pitcher. There is some dirt on it, so he rubs the ball on his shirt to get the dirt off.
At the end of the inning, the plate ump comes out to me and asks, "Did you miss that balk?"
"What balk?"
"Since I'm not used to balks, I really studied all the balk rules last night. Rubbing the ball on your uniform is a balk."
I told him I would kick his tail back to Little League if he ever called a balk like that.
1. No one gained an advantage.
2. It was a harmless move that actually helped the umpire from having to throw in a new ball and wipe down the other one himself.
3. We were game 2 of a double header among two obviously mismatched teams.
4. NO ONE GAINED AN ADVANTAGE!
Was he technically correct? Yep, it's right there in 8.02-a-3: The pitcher shall not rub the ball on his glove, person or clothing; But WHY does the rule exist? To keep a pitcher from defacing the ball. By knowing what the rule MEANS, you would never call this a balk. But if you only know what it SAYS, you'll ruin a good game (or in this case, a bad game) with a call like that.
You can apply the same thing to a hundred different situations in football as well. Holding, being inside the nines after the RFP, coach stepping over the sideline to signal in a play, etc. etc. All of these are fouls by the book. But they MIGHT or might not be fouls in your game. Knowing when they are and when they aren't is a key part of becoming a good official, and learning the difference only comes with game experience.
Know the rule book backward and forward, but don't be a rule book official.