Chess openings can be complex and tricky. While many heed the advice of their teachers and simply develop their minor pieces as quickly as possible, players at the top level are looking for a chance to activate their pieces.
To activate: to set in motion, make active or more active. Piece passivity is to be avoided at all costs. The opening of a chess game is controlled by the player who achieves more active piece play.
Why is this so? More active pieces, by definition, can create more threats. It is these perpetual threats that impede the development of your opponent's army. Being forced to respond to your moves each turn, your opponent won't have a chance to carry out his own plans.
If you keep this pointer in mind when you play through the openings of your games, you will find yourself in dominant middlegame positions more frequently. Your opponents will be afraid of you, and this will usually lead to passive play from them for the remainder of the game. Nothing could be better for you.
White to mate in two moves.