Perhaps it's less a question of what makes them hot for you, and more: "how can I make a character hot in a way I didn't know made a character hot." For example I have a character i regularly ask to be depicted in a beatiful dress; because i think that dress makes them look amazing, and I love it:
However, recently I decided to change it up, and get them in a dancer's outfit, and ho boi did that really set things off:
So i'd reiterate the question: we already know what makes characters hot for us. That's where we start the characters design, but how can we change that character's design in either clothing, personality, or physical characteristics so that they're hit in a way we hadn't considered before? What new, and exciting way can we take the character that we've never considered before, and might not consider without outside help, so that their all the more amazing?