Always have a plan.
Chess Axioms or Maxims

When you see a good move wait...you might find a better one.
Lasker.
The hands are a chess players worst enemy.
Cant remember who said this.

Two wrongs don't make a right but three lefts do.
My favorite.
Two wrongs dont make a right...but 2 rights make a u turn.
Two wrongs don't make a right but three lefts do.
My favorite.