Here is 1 technique. Remember, different textures of hair require different blades.
For a bald fade, start with a 5-O, make the next line with an OA, next line with a 1-a. You can use the 3-O and the 1 blade to take those lines out. However, you will have to freestyle with your clippers and clipperguards to take out the remaining lines. It's one of those things that you will have to see (watch for our dvds) and you will better understand.