Play toward weaknesses

When nothing is forcing, plans come from weaknesses — and the most reliable weakness is a pawn that no friendly pawn can defend. An 'isolated' pawn (no pawns on the files beside it) is the classic example: pieces must babysit it, and the square right in front of it becomes a hole you can plant a piece on.

The other half is space: pawns pushed further up the board give your pieces room to maneuver while the opponent's stay cramped. In the diagram, Black's d5-pawn is isolated — White's plan writes itself: blockade the square in front, then pile up on the pawn down the open c-file.