Well, now I came across a video by TrumpetDan to answer just that.
First of all, they clearly look at the stuff they've just trained on tape, choosing competitors that prefer the techniques they have just trained. In this case, they start with the oma plata and sweeps related to the oma plata control by watching Brian Morizi in action. What made the tape especially interesting is that I had the chance to roll with Morizi on one of my travels when he was a purple belt and remember thinking that he is basically an improved version of me. Better on every aspect of the game.
Wathing Morizi, they really look at every phase that happens during the build up to the technique performed in class. Dan stops the tape frequently and if something doesn't really show because of the angle etc. he demonstrates what's going on. The second part of the tape focuses on Gui Mendes sparring against Benny Dariush at the Art of Jiu Jitsu academy.
For me, this type of approach seems to work and I seem to be getting a lot out of these tapes this way. Oftentimes, when just looking at competition tapes on my own, I get anxious and skip ahead too quickly and basically never have the patience to rewind.
All and all, TrumpetDan is a former music teacher and along with analyzing tape with his students, he is also known for teaching positions and concepts instead of focusing on a large amount of techniques. You can get a hang of what I mean by checking his website clips at http://grapplingbasics.com/