Pattern # 19 , a dozen games. This technique is explained in ebook Fundamental Chess Patterns
A complete analysis is also available in The most important Chess Pattern
Basic endgame strategy, K vs. K+P. The side with the Pawn can win, if able to occupy the critical squares and to mantain the opposition.
The side without the pawn can draw if the opponent does not know the technique of opposition and the location of critical squares.
Additional different patterns can be found on this page of mine: Patterns
Side to move: