Generally in the openingyou want to concentrate on controlling the center squares. They are d4, d5, e4, and e5. That is why the most common openings focus on those squares. Once the openingis over and you enter the middlegame, the important squares depend on the position and the center isn't quite as important. It is still important to control the center in the middlegame. The center is so valuable because that is where you want to put your pieces so that they are most active. Pieces always control more squares when on the center than on the edge (except for rooks). In the endgame though, the important squares depend entirely on the position. But of course, if you want to win, you need to control the square that your opponent's king is on.
"The lack of a brain helps my skull think better." -oinquarki
So is there an article or something that can help me develop better position in my chess games. I've also been looking around the website and in multiple places I hear about focus control on specific squares like the E4 or F5 squares or something. How do you know which squares are important to control and which ones arn't?