Nobody whoever gave their best ever regretted it.
Don't do anything in practice that you wouldn't do in the game.
You might reduce Lombardi's coaching philosophy to a single sentence: In any game, you do the things you do best and you do them over and over and over.
Find out what the other team wants to do. Then take it away from them.
Nothing is work unless you'd rather be doing something else.
What makes a good coach? Complete dedication.