If you were to wear it in warm weather I think the shape and design of the neckline makes it a good JSK to wear without a blouse. If you were to wear a blouse I think something with a higher collar would be best like this in black or white (I would personally choose black.) For legwear I think something like this in black would be pretty because the pattern sort of mimics the print of the dress or maybe these which match the stars.
I definitely think a hair accessory with pearls would be a great option for your headwear. Something like this would look gorgeous with this coord. It’s sold out but you may be able to request they make another or you could use it as inspiration and just get a black headbow and add pearl accessories to it. One method that I like is to take a pearl bracelet and put bobby pins in the hooks either end and use them to attach it to your head, hiding the ends under the big hair accessory.
Maybe a little bit more Sweet but it’s sort of right in the middle of the two.