Slide down a curtain to make a big slash in the middle. Rewind time before it happened and it will still be there.
Defeating Enemies
When there is a ledge nearby, run up to an enemy and press Triangle to get behind them. Quickly press Triangle again to throw them either behind or in front of you, depending on which way you aim the Analog-stick. If done correctly you can easily throw enemies over the ledge and automatically kill them. This attack works on all enemies except for shadow creatures, Thralls and Bosses. Of course, it also will not work when there are no big drops or if there are walls.
Defeating ninjas
You can kill ninjas easily by using combo attacks and dual wielding a dagger-like weapon while they are not blocking, after you hit them once. Quickly press Triangle, Circle, Circle when they are not blocking for a one-hit kill.
Defeating women
The women are hard to defeat because they always block and you cannot jump over them. To easily kill them, run towards a wall and press Square. You will launch off the wall towards the nearest enemy and hit them. This is unblockable, but not undodgeable. This will also knock them down so you can stab them while they are vulnerable and use a combo on them when they get up.
Infinite sand
When you reach a save point and there is a vase with an extra sand slot, destroy it to get the sand. Save the game, then fall off a ledge or get killed. Load your saved game and destroy the vase again. This will allow you to get unlimited sand.