I find I am weakest in the endgame, which is arguably the most important part of chess. Usually when I reach the endgame I have an advantage, often a pawn or a "winning" pawn formation, but I am not sure how to capitalize and convert this into the win.

I was wondering, what are the key ideas to keep in mind when playing the endgame, and what can I do to improve my endgame play?

I hope this isn't too general, but I believe it is an extremely common problem.