This week I read a paper on how the chess AI Alpha Zero develops its chess knowledge. I was quite fascinated by the fact that what takes it the most time in its learning process is determining the factors it would use to evaluate the value of the pieces.
According to the paper once it's settled, its improvement is rapid and exponential.
As a player, you should always be aware of the value of your pieces and don't trade them unless it benefits you to do so.
Remember that rooks work best in open files and knights are more valuable in closed positions!