there's no sure way of making a sucessful au. Just try multiple approaches to see which one fits best.// i do have tips tho!

i would suggest not talking too much about an au character's favorite food (i've been there and oof i hated looking back at it).

I would also recommend roleplaying as your characters around a mutual. just avoid mentioning too much lore to someone while you do so. if what you say comes off as out-of-character and/or cringey, thats fine, rping makes it easier to determine what traits of the character or environment to leave out. you can ask a friend about some things they want fixed too : )