Understand the object of the game and how it's achieved. To win, you need to checkmate your opponent's King. This means to get his King in a position where he will be captured no matter what -- he cannot move and no other piece can protect him. Checkmate — that is, the end of the game — can happen in three moves or it can happen in 300. Most longer games are different.
The secondary goal is to get rid of all your opponent's pieces (thus making checkmate easier). You capture pieces by landing on the square they occupy.
This is all going on while you're protecting your own King, obviously.
Know how to put your opponent's King in "check." This is like checkmate-lite. That means the on next move you could've captured him, but he can still flee or another piece can move to defend him. The game isn't won, but it certainly looks like it's in your favor.
When this happens, be sure to verbally say "Check." Your opponent must then do one of the following:
Avoid the check by moving their King to any vacant square not attacked by another piece.
Block the check by placing any piece between your piece and their king.
Capture your piece that is putting the king in check with any of their Know that you can not put yourself in check. In other words, you cannot make a move that exposes your King to capture on the next turn. This means you cannot move your King into an area an opponent's piece can move to the next turn. You also cannot unblock your King from attack, that is, move a piece that would expose your King to direct attack.pieces (including the king himself).