>>543943206
I don't have it down to a science, but something along the lines of
>big boobs
>big butt
>cute tummy
>maybe some feet
>occasionally a tasteful bulge.
Pick any of those features at random and sprinkle them into your character card art. Everyone's aesthetic tastes are different, so there's no one-size-fits-all design that will catch everyone. You can appeal to certain sets of people with specific designs, though.