how do you make a fan fic character?

Truthfully, its not to hard.
You can even take yourself and make it into your character. That's what i did.
My character looks pretty much just like me, except she's older.
But you can base it off yourself and maybe add some highlights, change the eyecolor, make her/him wear something youd love to wear but cant.
There are endless possibilities.

Just come up with some good and bad traits for your character, too.
My character is a very good artist and can be a very nice person, but she's easy to anger and very sensitive.
Dont make your character to perfect, or noone will want to learn/see them :]

If there's anything else you'd like to know, just message me ^_^

Well you should be more specific. do you mean how to make it on paint or think up a char? Well if you want paint, basically what u have to do is choose a character from the show, look at a pic and draw the shape of them. draw a different hairstlye and clothes, give it a name and give credit to the owner of the character its based on. As for creating 1, decide what their name is, personality, write a short bio w/ a relationship ( u can create another char for that). It could be based on you or just made up. Whatever you wanted to do I hope i helped! (p.s. If you do a color over make sure to give credit to the original artist.Ppl get mad about that kind of thing!)