The problem with chess training always has been that there is way too much good advice. With tactics, it took me 18 years to separate the wheat from the chaff.
The book of GM Hellsten about middlegame strategy contains 826 potential relevant variations. But learning them is like learning an encyclopedia by starting from the letter A. Nobody can do that, unless you are an idiot savant of some sort. I just have the idiot part covered, so I got to turn to some chaff separation first.
I was happy that I could separate quite some chaff, until I found the two subjects that are the place to start: exchanging pieces and pawns. It turns out that there are about 10 types of positional exchanges, and the actual study of them is pretty straight forward.
But studying pawns is a different animal. Here again, there is way too much material to study. In the book Hellsten dedicates 475 variations to pawns.
After some time I found that the two most important areas are where the pawns have an effect on the LoA landscape (LoA = line of attack): piece activity and restriction.
You can use your pawns to increase the activity of your own pieces, and you can use them to restrict your opponents pieces.
You can do a lot more with your pawns of course, but that only distracts you from fully mastering the building of a viable LoA landscape. GM Nigel Short once said, "Modern chess is too much concerned with things like pawn structure. Forget it, checkmate ends the game!"
This reflects the difference in pawn moves that affect the LoA landscape and pawn moves that are designed for a favourable ending. You first have to master the building of a LoA landscape.
CM Can Kabadayi happens to have written the two following books about pawns:
The Art of Burying Pieces and The Art of Awakening Pieces.
The first book is about restriction, and the second book is about improving the activity of your own pieces. I'm studying both books currently. Much recommended!