Creating new records of organisms or their activities is one of the neatest accomplishments in science. Photography is a great way to do so, stuffing large amounts of information on size, color, and morphology into one or a set of images.
Unlike the other photography activities mentioned in OPTKS, collection of natural history observations is much less reliant on planning and more reliant on chance. It could be coincidence that puts you in the same place as a mass shrimp cheliped-shedding event (hypothetical, of course?) or that a certain species shows up in your surveys. Being prepared for such events, though, can help you make the most of them.
Of course, understanding your equipment will help you make rapid adjustments for photographing events as they unfold. It may also be useful to keep a ruler or some sort of scale with your photography equipment so you can show the magnitude of an event or organism.
If you find a new organism, chances are you’ll keep the specimen and pickle/preserve it. Since formalin and alcohol tend to leach colors and deform tissues, a good practice would be to take a suite of pictures of the organism before you fix it. Take images from many different angles and of diagnostic features. Include scale and possibly color references so you can make measurements later (and have a good idea of the organism’s colors after you pickle it). This type of photography is known as photovouchering.