You could try clicker training your cat. It's a technique commonly used on dogs, and I've used it on horses, but it should work on cats too. You'll need a clicker (ask from your local pet shop).
The basic idea is that you give a clear signal, and if the cat starts doing what you asked for, you immediately click the clicker and the cat gets a treat. The click becomes a cue for the cat to help understanding what exactly you liked. After a few times, it should be pretty clear for the cat how to make you give out treat; now you can raise your expectations by clicking only when the exercise is performed somewhat closer to your final intent. The cat will try various things when the old way does not work any more and very probably will stumble upon the correct thing to do.
You should start with very simple expectations, and move slowly to more complex ones. You want to be sure the cat is able to stumble on trying the next step. For example, when training your cat to sit, you give signal and click+treat when the cat stops moving (if that's too hard for your cat, you might have to start at "slows down"). When signalling stops the cat reliably, prolong the time cat has to stay put before clicking. When that works, click+treat only when the cat lowers its rear body. Next, only sitting down.
It's up to your imagination on what tricks you want to teach; for photography, you'll probably prefer tricks that involve staying still in a certain pose. Figure out the steps for cat how to get to that pose and start training.
When the cat has learned a trick, you can stop clicking (there's nothing more to learn) and just praise the cat in a usual way. Try to keep the lesson fun for the cat, and stop the before the cat gets bored. It will take several sessions to get to the end, but you will have a trained cat. Isn't that cool?