I have formulated a rule for myself which I call the principle of the worst piece:"In positions of strategic manoeuvring (where time is not of decisive importance) seek the worst-placed piece. Activating that piece is often the most reliable way of improving your position as a whole."
There is, of course, a very famous saying from Rueben Fine:
"I'd rather have a pawn than a finger."
It's often quoted during analysis.
One of my favorite sayings, though, came as a response to this.
About 40 players were watching an online broadcast of a major match.
One of the players was a pawn down, and there was some argument as to how much compensation the other had.
One of the masters present quoted Fine, "As Reuben Fine said, "I'd rather have a pawn than a finger."