Hi! I'm writing a story about a rather powerful main character. She's basically God in the story, but I still want her to have flaws. Any tips or advice?
Hello! Fear not: powerful character in no way equates Mary Sue-dom.
My first advice would be to take a look at some uncensored Greek myths (okay, maybe the best idea. How old are you?) and see exactly how much drama went on between the gloriously flawed, semi-omnipotent deities.
Endow her with flaws the way you would any other character: she could be like Zeus, and be crazy promiscuous; she could have an explosive temper and a shit-ton of misdirected rage, like Hera; she could occasionally cause Earthquakes when she’s feeling cranky, like Poseidon, and so forth. These gods are all great, beloved entities, still prominent today, but it’s the “human-ness” of their dispositions that makes them so memorable.
You could give her a bunch of semi-omnipotent buddies to bicker with, or you could just show her escapades interacting with mankind; either way, there’s an insurmountable amount of directions you can go with this, and I’m certain many of them can be incredibly interesting.
Best of luck, and happy writing! <3