The Yau method is a faster method than the beginner method, used by the world record holders.
The first step of Yau is to solve two opposite center pieces.
Next, solve 3 edges of the bottom center(The center you are going to solve the cross on)
Next, solve the 3 centers for the 3 edges.
Next, solve the remaining edge and center piece.
Next, solve the remaining edge and center piece. Then, solve the cube like a 3x3.
Just like in beginner's Method, there is a weird thing about 4x4, and that is parity errors. These is due
to the absence of center pieces in the 4x4. There are two parity cases
and there are algorithms to solve each of them.
Now you have a completed 4x4!
Below is an in-depth tutorial on the 4x4 Yau Method
For online tutorials, click here!
This method can be applied to bigger cubes such as 5x5. See video below