Good positional understanding is one of the main criteria separating masters from club players. The problem is that it can be one of the toughest areas of the game to improve. Why is that? Because it is often left out of lessons for beginners, and there is next to nothing for beginners out there that covers positional chess!
The Backward Pawn – Positional Chess for Beginners
https://www.ichess.net/blog/positional-chess-beginners-castellanos/
How To Play Positional Chess
https://www.chess.com/article/view/how-to-play-positional-chess
I find some players get confused by the difference between tactical and positional chess, especially because both skills are needed to play a strong game.