Here is a common pattern: a hotly contested piece or pawn near the middle of the board. In a typical case each side has several pieces trained on the square in contention—perhaps an equal number, suggesting that if you try to take the piece or pawn there, you will gain nothing and perhaps lose some material when the smoke clears. You take, he takes, you take, he takes. But it still is important in such cases to imagine liquidating the position, with all possible exchanges exhausted; for it may be that you then will have a kicker in the form of a fork or skewer against the last piece standing.
Look at how the logic applies here. The contested point is White’s pawn on e5. Black attacks it with both knights and his queen; White protects it with a bishop, his queen, and the rook behind the queen. So if Black takes the pawn with his knight on d7, White recaptures (or could recapture—we’re just imagining possibilities) with his bishop. If Black takes again with his queen, White retakes with his queen. If Black takes a third time with his last knight, White retakes a final time with his rook. The rook is the last piece standing, and this still is true even if the move order goes a little differently than just sketched. Now don’t give up once you see this; look for a kicker against the rook. The key is to remember to remove from your mental picture of the board all those pieces that were exchanged away in the interim: White’s bishop, queen, and rook, as well as three of your own pieces. With those off the board and a rook on e5, you should be able to see an alignment that results. White’s two rooks are on the long, dark-squared diagonal with nothing between them. Now Black plays Bf6, a move that wasn’t possible in the beginning because White would have taken the bishop with his e5 pawn. In this position the move skewers White’s rooks, both of which are loose and one of which will be lost. You have to keep track of the tally, of course. White will take one of Black’s pawns while Black is playing BxR, so in the end Black ends up losing a pawn, two knights, and a queen, but gaining a pawn, a bishop, a rook, and a queen. In other words, he wins the exchange.
Assuming he sees all this, too, White will not play even the first move in the sequence, BxN. He will instead accept the loss of a pawn to Nxe5. This is another illustration of a general point: in chess games between good players it is relatively uncommon to see skewers, forks and the like actually carried out. Both sides see them coming and avoid them by accepting lesser losses. But of course the tactics nevertheless play a crucial role in the game, because the potential for them dictates each side’s moves and the losses to which each side decides it must consent.