How do I design a main character? Easy—
I have a method I’ve used for over thirty years and it works for me and it’s simple (which is why I still do it) and this is it:
First, you figure out what your story is about and write that down in no more than two sentences.
Next think what kind of main character will best fit your story and describe that character in no more than two sentences.
That’s it! You’re all done!
Okay, it’s true that many writing guides say you should flesh out your characters. They’ll probably include a list of characteristics for you to describe that’ll go on for several pages.
Guess what? If you have your story and main character firmly in mind, then all those things are ‘extra’ and can be added to your main character’s two-sentence description as you write and such extras are needed to fit the story.
This method works, it’s efficient, and gives you a whole lot more time to write — or do other things, like live an actual life — than any other method I know.