Modeling was one of the things that drew me into NLP. Unfortunately, though it is one of the most discussed benefits of NLP it is one of the least taught. During my practitioner training I was the only one interested in modeling. There are only three books that go into detail on it that I know of, "Modeling With NLP" by Robert Dilts, "The Emprint Method" by Leslie Cameron-Bandler, and "Advanced Behavioral Modeling" by Wyatt Woodsmall, generally known as the top modeler in NLP. There are other books that cover modeling as well, usually unconscious modeling.
IMO unconscious modeling it the best route for most people to go. It is easier and works for most skills. It is related to rapport and the techniques involved are similar. In establishing rapport through matching and mirroring you are temporarily modeling the person you are in rapport with. The basic idea in unconscious modeling is to become the other person to the extent you need to learn the skills you want or adapt the attitudes you want to have. There are several techniques such as Deep Trance Identification which is the most complete form but also the one with the most side-effects, the New Behavior Generator which is probably the easiest to do and the most common modeling technique in NLP books, and others such as Putting on Heads and Borrowed Genius from Imagestreaming. Some Paraliminals such as NBG and IPM are good for modeling.
Conscious modeling is a more complex task and there are several ways to do it. What I was taught is that for a specific ability you need two groups of people, one who does the skill well and one that doesn't. You take each group and map out their strategies (this is where eye-accessing cues are very important) , metaprograms, states, submodalities, and beliefs for each chunk of the skill. Someone might have set of distinction s in one context and another in a different context. You compare the maps and decide what information is essential and what is not. Then you test it by installing the model using various NLP skills into people who can't do the skill and take away parts until you have a model of all the essential distinctions for the skill you are modeling. Obviously this is a complex task and would involve a group of people. You could do it one on one but it would be less complete. IMO this is not practical for most people, trained NLP practitioners for most purposes.
As for modeling in Photoreading, in a sense the whole Photoreading course is a model of how it is done. It has even been streamlined since I first took the course and is a much more effective program then when I first took it. I'm not familiar with the Home Study Course or the new Photoreading Activator Paraliminal, but in the playbook I got for my original class there were two Paraliminals using the NBG to install the steps to the Photoreading Whole Mind Reading System.
You can use any of the techniques mentioned earlies such as DTI, NBG, or the techniques from Imagestreaming. It would be best if you can somehow observe the person demonstrating the skill. It is also possible for you to model yourself by taking competence or confidence you have in one area and using submodality mapping and/or anchoring to bring that into your ability at Photoreading.