The waist was also kind of baggy while the hips fit really well, so I decided to wear this waist belt from Asos, that I've had for a while, but never worn.
The dress is kind of clingy and subject to static cling which is really annoying. But I didn't really do anything about it. It wasn't as bad the more I wore it. Probably because of the humidity in the air.
Dress: Gwynnie Bee (not sure what brand)/ Necklace: Lane Brynant/ Belt: Asos/ Shoes: Torrid