There are two important things to do in chess: offense and defense
Offense is the art of attacking
Defense is the art of supporting pieces and preventing mate
There are two things to remember in offense: pins and sacrifices
This puzzle below show how strong a pin is. Some people say its a draw but is not because of the pin:
Black's previous move pinned the queen but white's next move is a killer.
Sacrifices are very powerful sometimes. You can use it to checkmate your enemy. A puzzle will make you understand:
This one is good:
Defense is simple. This is an example:
Both of the intend to attack queenside later.
If you need more facts wait for the part 2.