When playing a game of chess it is important to develop all of your primary pieces early on in the game. If you have primary pieces that are still sitting on the back rank by the time you reach the middle game, then you have given your opponent an advantage in the game. All pieces need to be developed in order for you to have the tactical advantage in the game. Often times a player will leave a rook sitting on the back rank doing absolutely nothing. If you find yourself doing this, then you need to change. A rook is a very valuable piece and leaving it sitting safely tucked in the back rank is creating a situations where you are basically giving your opponent a one piece advantage.
A general rule of thumb is to move each piece once before moving any piece twice. This may seem very difficult to achieve in game play, but it does provide a great advantage to you if you are able to carry out this strategy. If you are able to safely develop all of your pieces early on in the game you will definitely have a lead in tempo over your opponent. Conversely, if you play too conservatively, you will allow your opponent to gain tempo and your opponent will be able to put you on the defense for the entire game.
Do not forget to develop your king by castling. Generally this is done on the king's side, not the queen's side. This is also usually done during the opening, or within the first fifteen moves of the game. A winning strategy is one where you are able to develop and cautiously advance your pieces before your opponent has the chance to do the same.