Body Line PDR Dent Repair - Student Question

Recently, one of my past students sent me this photo of a dent he was doing today (after photo coming later). He did also mention, it was kicking his butt too, LOL. No matter what level a pdr tech is at, body line dents will always at some point be a challenge. It all depends how deep it is as well. This one happens to be an average good old whack from another car door.

Now my purpose for this illustration and explanations was to help him stay in good habit and so he can compare what he had learned from me in person. I like to keep good communication going and this one of many options seems to help.