Run off a ledge without jumping and initiate a jump at any time during your fall.

Additionally you can input a direction while jumping to change your momentum and move in the pressed direction.

This extends your jump range quite a bit, making hard jumps super easy and enabling skill jumps that are otherwise impossible.

By pressing the crouch button while in the air near an object you can increase you maximum jump clearance.

HOWEVER

When crouching in the air the players top-speed is slowed and all momentum will completely cancel out.

This necessitates a timed crouch input as close to the ledge your trying to reach as possible and opens the floor to failed jumps due to an early crouch input.

The Throne room has many skill jumps to rat spots that are impossible without crouch jumping.