The rook vs knight endgame is one of the most challenging end games that a chess player will come across but is very important for every player to know. The key to winning with the rook is to first capture the knight. This is done by moving your pieces in a way that will limit where the knight can move. One of the big mistakes players make is trying to check the king before the knight is captured. This is not the way to win. You need to have the knight on the rim of the chess board and then you need to move so that wherever the knight moves, he will be captured. This takes a lot practice but is very useful once you master it.
Click the video below to watch a detailed explanation on the rook vs knight end game.