Anupam, I addressed the purely photographic problems of working close up. They are much more trivial than many of us will admit. Exposure, controlling light, focusing, composing. It isn't quantum mechanics.
The problems of dealing with live subjects are something else again. In my limited experience, that's where the real difficulties are. With the organisms I've spent much of my life shooting, managing the subjects separates the best workers from mediocrities like me. I used to study their pictures to try to puzzle out how they induced their animals to perform front and center.