Black has a loose rook at d7: a target. White’s queen can attack it by moving to h3, g4, or f5 (you attack rooks diagonally, and bishops horizontally or vertically), but none of these moves attacks anything else at the same time; the path to the king is blocked by the pawns in front of it. So consider what other resources White can bring to bear—what forcing moves, and with what results. Experiment with the knight. It has an easy fork with the check Nf6+; Black has to reply g7xN, not only to avoid losing the rook but to avoid being mated with Qxh7. But then a line to the king has been opened; now Qg4+ attacks both king and rook, winning the exchange.

If you need to move an enemy pawn, whether in front of its king or elsewhere, the most common method is to take something it protects. But another technique to remember, shown here, is to imagine sticking one of your pieces en prise to the pawn and consider whether it makes an interesting threat that your opponent would feel obliged to extinguish, thus leaving you with an open line on which to play a tactic. Or maybe he will decide that he can't afford to extinguish the threat by making a capture because its side effects are too severe (i.e., the queen fork)—so instead he has to let you push your first threat forward.