Winning a game of chess is not easy, especially for the inexperienced chess player. One difficulty that many newer players face is how to capitalize on an advantage that they have in a game. If you are in the lead in the game, you have momentum, and you are ahead in pieces, but have difficulty placing your opponent into checkmate then you are having trouble winning a won game.
Many inexperienced players get up a piece but have no idea how to proceed. Instead of following important chess guidelines, inexperienced players will often to the opposite of these basic chess guidelines. Sticking with the basics is probably the best way to make sure that you win your won games. Trying to get overly complicated, or trying a new theory that you read about will not help you to gain the victory that you are looking for. Some of the basic concepts to stick with include controlling the middle of the board, using tactics such as pins and skewers, and keeping your pieces properly defended.
Sometimes when an inexperienced player is winning the game that inexperienced player will get in a hurry and simply make a silly mistake. Other times the inexperienced player may get overly confident that they will win and forget that they are playing a competent opponent who is looking for any possibility to win the game or create a draw. Chess can be somewhat ruthless since it is generally a good idea that if you are defeating your opponent, to go for the kill and to not "let up" on your opponent. Play smart chess and stick to basics and you will likely win your won games the majority of the time. Study checkmate basics to help from finding yourself chasing your opponent around the board for ten turns.