Original corner first method

Step4. Middle layer edges. 

Orientation of edge to corner is described in figures because it makes easy to understand the situations. I only care about edge to edge orientation, not edge to corner. These are only representatives. You had better to remember mirror images.

These cases you may orient two pieces simultaneously.

Step5. Center cubes edges. 

In this step you can orient center cubes using only M and S slices.

If you can not orient the middle layer center cubes, you have to do this.

Step6. Top layer edges. 

In this step, I use basic algorithms which everybody learns in first. You have to remind that you can avoid some complexed cases in step7 if you

In some cases, you can orient two pieces simultaneously.