I am currently reading The Official Vince Lombardi Playbook by Phil Barber. This is a great book about one of football's Hall of Fame coaches, that includes actual hand written plays and notes from Lombardi along with interviews from some of Lombardi's top players.
For youth football coaches, Lombardi emphasized perfection, drills and repetition. One of the main points of success for Lombardi's Packer Sweep was the endless repetition; 30 minutes sweep time per practice and at least 30 reps weekly in practice on just the sweep play. Lombardi focused on the sweep to set up other plays, like the off-tackle trap and full back cut back. Remember youth football coaches, your play calling should not be random offensive plays but a series of plays to set up the next play, like a chess game.
Lombardi liked to keep things simple. Lombardi once said "Football is two things. Its blocking and tackling. I don't care anything about formations or new offenses or tricks on defense. You block and tackle better than the team you are playing, you win."