Size: Although only part of it, breasts must be of a perfect size. C is ideal unless they can be bigger but still firm.
Shape: Boobs should be perky and stand up, and be a round shape.
Texture: Should be uniform, and firm like styrofoam
Areola: must have a nipple on it
Smell: Should smell like warm milk or spices
Finally, the quality of the boobs has nothing to do with whether the person is a fully actualized transwoman or a cis woman with real ovaries, the boob and its beauty is separate from all of that and anything anywhere since what has an appreciate about that is what it looks like not what you think someone should want to look like if I do say so myself.
Thank you for listening.
Its greatness is judged by the one who holds it, and most holders will not consider it as an isolated entity separate from its owner, for it is worthless as such.