Here are some tricks you can use.

Building A Wall

    Usually, whoever gets to the middle first wins.  So you should bring up your pawns double each time, then bring your bishops up, and finally your knights. this gives you a good layout and  a lot of space for your king.

Giving Bait

    You are giving bait if you put a strong piece right where a different colored  piece can kill the piece, but  have another piece ready to move in to kill the piece taking the bait.

Making The Right Choice

    Remember to consider all options on the board.  Say you could change a pawn into a queen, and a king was fully protected besides the front of him.  If you chose the pawn,a queen would come down near the king and attack.  The king couldn't move so it would be checkmate. 

Castling

    If there is nothing between your king and rook, and you haven't moved them you can do a move called the castle.  This is where you can move your king to the knight's spot and move the rook to the bishop's spot.  (It can go through queens though.)

Rook Roll

    When you have a queen and a rook,  you move the rook down the rows with the queen forcing the king to go all the way back.  Then, you can cancel all the king's  moves one row at a time until checkmate is achieved.