DD8 is the same here - hates clothes and would much rather be semi-naked at all times.
I, on the other hand, am erring on prudish - I don't like little triangle bikini tops, or short shorts, or bare midriffs.
I don't sugar coat it or make a big deal of it. Wearing clothes is a house rule when visitors are around. I just tell her it's rude and disrespectful to herself and to others to not wear clothes. So she gets a very basic "so and so is coming over, go put clothes on", or "someones at the door, go put clothes on". Through to "if you don't want to wear clothes, stay in your room. We don't want to talk to you undressed". No different to putting their pyjamas on at night, and not getting dessert/movie/story etc until it's done.
As far as crop tops etc - DD's best friend is quite developed (and a little "heavy) and wears these, so DD wants to wear them too, just to be the same. Does your DD have anyone she likes/admires/looks up to, that wears them, or could buy her some as a gift?
I"m not the best at these things, and I'm sure others on here will say my approach is going to scar her for life. But I do think modesty has to do with self-respect and manners. Saying pardon, please, thankyou and wearing clothes are all requirements in my house..... and they still ignore me anyway!!!!