Back to reporting fouls to the Referee, the best thing you can do is report it in much the same way he would announce it. Something like:
"Offside, number 34, defense. He was in the neutral zone at the snap."
"False start, number 78, offense. He started early."
"Facemask, number 99, defense."
"Pass Interference, number 88, offense."
"During the runback, illegal block below the waist, number 37, receiving team."
"Kick catch interference, number 55, kicking team."
"Illegal formation, more than four in the backfield, offense; holding, number 45, defense - before the ball was thrown, he tackled a receiver."
As much as possible, use "Offense, defense, kicking team, receiving team, passing team, fumbling team, return team, or the actual team names (Central, Johnson, State, etc.).
Avoid "colors." Never use "Team A" or "Team B."
After the initial report, the R may need to know the actual spot of the foul, so be ready to give him that info. Then stand nearby, off to the side, but in his sight, as he gives his announcement, in case he needs to be reminded of the number(s), and the down number.