Pawn endgames have concepts and advantages to be exploited. The main idea behind a pawn endgame is not mate, it's getting your piece to your opponents back rank and converting it to a queen. In your middle game focus on creating endgame situations in which your pawns are the most lethal by keeping the following themes in mind.
Activate your King
As the endgame draws closer bring your king out to the center to do battle. It is now an important offensive piece. I think in the endgame they give your king a value of 4 or 4 and a half. An earlier activated king in a equalish board can decide the game.
A passed pawn is a pawn that has no other pawns in front of it. It is very powerful. A connected passed pawn is when the passed pawn has another pawn protecting it. The idea is that your opponents king cannot kill your pawn without killing its protector first. If it kills the protector then the king will be out of place to catch the passed pawn when it goes for the back rank.
Split Pawns
Split pawns are pawns that are split apart at a distance that if the king attempts to kill one of them the other one can’t be stopped trying to convert to a queen.
Outside Passed Pawn
An outside passed pawn is a passed pawn that is away from the where most of fighting will occur and has no pawns in its path. It is like split pawns because the opposing king must leave one battle for another. The person with the outside passed pawn should lead the opposing king away while moving there king towards the battle, in the opposite direction. In most cases do not try and defend your outside passed pawn as its power lies in allowing your king to eliminate your opponents pawns.
Keep these ideas in mind during a middle game that seems as though it will end with only pawns. It takes only one well placed pawn to win the game. These concepts should also be understood: The Opposition, King vs King and single pawn and zugzwang
See also: Endgames in Chess Isolated pawn
Connected Passed Pawn