At beginner levels, games are frequently won and lost with the four move checkmate, also known as Scholar's Mate. It's most commonly played with 1. e4 e5 2. Qh5 Nc6 3.Bc4 with Qxf7# on the next move. It's very important to defend your weakest point from checkmate. That's the f7 pawn for Black and the f2 pawn for White. As long as you're careful to block opposing pieces from attacking that square, you can reach a good position.
