Knowing when and where to use your knights can be the difference between winning and losing. Knights are very versatile with their ability to leap over other pieces on the board. The knights are the only pieces that can accomplish this important feat. Much of the strength of the knight depends on where it is positioned on the board.
It is important to spot gaps in your opponent's position where a knight cannot be attacked because your opponent's pawns have already moved past that position. Knights are generally easily chased away with pawns. Once you find a gap in your opponent's defense you should place you knight into that position. A knight that is not facing any immediate threats and that cannot be attacked in one or two moves by the opponent's pawns (since the pawns have already moved too far forward) is a valuable asset in the game. An unchallengeable knight on the fifth row is a strong asset, and a supported knight on the sixth row usually decides the game.
Generally it is a bad idea to place a knight on the edges of the board or in the corners of the board because this dramatically limits the moves that the knight can make. It is similar to placing the knight into a cage with only one way out. Knights are generally most beneficial towards the center of the board.
It is also important to keep in mind that a knight is one of the best pieces to deliver a fork. A fork is where a piece can threaten two pieces at the same time. Your opponent has to decide which of the two pieces that you are threatening to sacrifice. Knights can be very sneaky in delivering a fork.