Well, “superhero” generally divides into the following types, I think:
- Normal human whose lifestyle or dedication to a particular study has resulted in enhanced skills. The best example is Batman. I would argue that Sherlock Holmes also falls into this category.
- Normal human who has had an extraordinary talent, something beyond human capabilities, thrust upon them. Spiderman and the Fantastic Four fall here.
- Extraordinary human who has had extraordinary abilities from the very start. Superman, Thor, the X-men.
Type 1 is the oldest. Zorro, the Shadow, the Green Hornet, even Tarzan … these are heroes who could just as easily show up in detective stories as in comic books. Your story is probably going to focus more on the crimes they are working on than on their “powers” because, technically, they don’t have any powers. This sort of superhero is great for empowerment stories, stories where you want to tell the reader that anyone should be capable of doing the right thing and being the hero. You might also want to include discussions about why the hero is doing what they do.
Type 3 is the opposite extreme. These characters are outside of human capability, and have a bit of a “chosen one” air about them. Normal people have no hope of measuring up. Your story is probably going to focus on bigger stakes: world-threatening aliens and that sort of thing. They’re great for wish fulfilment stories, stories where normally insurmountable problems can be made to go away by the appearance of a saviour.
Type 2 falls somewhere in between. These heroes whisper to the reader that, given an extraordinary circumstance, their power could be attainable too. Your story will probably focus on how they adjust to their newfound power, or what that power means: as I understand it, an ongoing theme with the X-men is how their power separates them from humanity. But aside from these very personal “adjustment” stories, you also have a free range of everything from small-time crooks to supervillains bent on world domination.
These are all generalisations, of course, and generalisations always come with exceptions. (See what I did there?) It’s possible and it’s been done, to have a superhero who is technically of one type face concerns associated with a different type. (Edit: notice that I listed the X-men as an example of a type 3 superhero and then brought them up again as an example of the concerns of a type 2 superhero.)
The next big thing to think about is how widespread the phenomenon of the “superhero” is. I think this makes a huge difference to the tone of the story. People nowadays seem very fond of worlds where superheroes proliferate and each big city might have a superhero league or two, but I’ve always preferred the “lone hero” model where the hero is pretty much the only superhero in the nation … possibly even the world. I think that a “many superheroes” world leads to a tendency to focus on the issues faced by the superhero elite, at the expense of the normal human populace. And that’s not a bad thing … it’s just a matter of taste. I think the “many superheroes” model also lends itself more easily to comedy.
All that being said … it would be interesting mix up these elements and see what you get.