If you are looking for photorealistic results, start your prompt with curly brackets and include the details about what exactly you want to create there. Since the subject is usually the most important thing about the generated images that would be the thing to start with.
However, in some cases, it would actually be smarter to start with the type of picture you want to create. That is true for scenarios in which the type of image is hard to create using ai and therefore you need to emphasize the importance of the specific image type/style by placing this in the front of the prompt.
This description itself should include the subject , the action he performs and adjectives that describe him best. The subject can be a person, animal, creature, robot etc. But you need to be specific about it. You can : write a military person standing on street . But it is better to write: A military old man with a machine gun walking on abandoned street.