When learning the rules of chess we discovered that the primary goal is to checkmate the opposing King. That means we must conduct our 16-man army as a unified "command", working together to deliver checkmate. Right off it is good to know what each chess piece is worth, what its value might be compared to the other chessmen. If the weakest unit, the pawn, is given a value of 1 point, then the following is accurate:
Queen: 9 points
Rook: 5 points
Bishop: 3 points
Knight: 3 points
Pawn: 1 point
Before starting play we should note what lies ahead, and what happens in a typical game of chess. As Grandmaster Arthur Bisguier has said, "A well-played chess game has three stages. In the opening, the players bring out their forces in preparation for combat. The middlegame begins as the players maneuver for position and carry out attacks and counterattacks. The final stage is the endgame when, with fewer pawns and pieces left on the board, it is safer for the kings to come out and join the final battle."
It happens that every chess piece works better in the center of the board, so look to control that sector from the opening onward. Bring every piece to an active squares where it influences the center, and rarely move any piece twice until the whole army is mobilized. Make sure to castle quickly - and do all this by moving only one or two center pawns forward.
Trade or exchange piece for piece of equal value, unless something definite is gotten instead, such as a weakness to attack. Be alert and look for ways to get a piece from the opponent at little cost, or threaten his forces. Watch for tricks and traps, because the opponent is crafty! Try to Understand the purpose of the move just played, and the general plans available in the current position.
When the endgame approaches checkmate will mostly be delayed until more of the enemy pieces have been captured. That usually requires escorting your pawns toward their Queening squares, forcing their capture by stronger enemy pieces - and that clears the way to checkmate.
Lastly, have fun and enjoy the unlimites world of chess!