Don’t make fan art because you don’t own it. You don’t own the IP.
I can say I have been 50/50 on the fence on the issue of creating fan art as I thought if you create a totally different style while using the character its to share it online and even make some prints off it.
But Sean makes a strong case for not making fan art around a IP as its violates the copyright of the IP (100% illegal).
You can only do fan art if you have written permission from the copyright holder. Some artist say you can do fan art as long as you draw it in a different style or if everyone else is doing it.
The reason is you can’t make fan art and publish or sell it is because you derive value from the fan art. Even if you don’t sell it you also derive in-direct value.
After listening to the podcast at least a couple of times to let it sink in, I think its wrong to do that as just because everyone else does it does not make it right. Call it my own moral discretion. I would to in the same won’t want someone else to derive value from my own creations without permission.
When you can make fan art?
Reverse engineer how they made it
This is to learn how technique was used by the original creator. You want to breakdown the methods used and how he went to create the style or drawing.
Many creators starting out would do this starting out as it gets them to learn how something popular is made and learn the craft.
Note: I don’t think it would be wise to publish the work but maybe as a case study on the creation process.
If you want to sell your fan art?
Another way is to do a remix as mention by Kirby Fergurson about how to take old ideas and combine them with new ones to create something new. This method of remixing may set you on creating your own characters and make a remix of things that exist. Nothing is new under the sun.
This way you have a totally new creation and the old inspiration will be somewhere inside but its not a direct copy.
I do think sometimes is ok to share your fandom with others by paying homage in various mediums. See the remix of Star Wars Episode 7 Remix edition.
Hopefully this helps I probably won’t do any fan art let alone publish them except under the studying it for techniques and learning the craft.