Yau Method is a 4x4 speedsolving method, but it can also be applied at bigger cubes.
1. Solve 2 opposite centers and 3 of the cross dedges
2. Solve the remaining 4 centers
3. Complete the cross
4. Pair up the remaining dedges without messing up the cross
Cross is already done when you start the 3x3 part
It can be hard to find the 3 first crossdedges
Centers are a little bit harder.