Figure[White to move]

Here is nearly the same pattern turned sideways. Black has two loose pieces: his rooks. Lines to them cross at several junctures (e.g., g1 and h6), but the only useful intersections are those that allow the rooks both to be attacked on diagonals, making it impossible for them to defend themselves by going after the attacker. So the winning move is Qe3, picking up a rook a move later.

This much is easy, at least if you are alert to loose pieces; but now notice a couple of finer points. The fork only works because of the pawns at b2 and h3. Do you see why? The pawn at b2 is critical because otherwise Black could move one of the rooks to protect the other. It always is important to ask whether your opponent would be able to break a fork by moving one of the pieces out of it to protect the other, to check your king, or to otherwise create trouble. It's an especially important issue when you are forking two pieces that both have mobility, as these rooks do.

Meanwhile the pawn on h3 is essential here, too, since otherwise 1. Qe3 is met with the knight fork Ng4+. You want to ask in any position not just whether you have any forks to give but also whether the enemy does—and whether he will have any after the move you are considering. This is particularly important when, as here, Black already has a knight check to give on g4. This means you have to think twice about putting your queen on a nearby dark square where it might get forked. Fortunately it's not a problem in this case because you have a pawn at h3 guarding the forking square.