Comment by QuantumGood

Common advice to beginners:

"Improve the position of your worst placed piece."

For better players, determine which is most effective:

1 Improve the position of your worst placed piece.

2 Exchange or minimize the potential of your opponent's best-placed piece (e.g. trade off their bishop on a long diagonal)

3 Maximize the potential of your best-placed piece (sometimes by a sacrifice)

4 Prevent your opponent from developing some pieces

This is over-simplified, of course, but the balance of the position must be taken into account.