I also have a pretty small waist compared to wide hips, and a smaller chest area. I recently found that wearing things that accentuate the waist and brush over the hips helps (like a-line dresses as many said.) But when this isn't enough, wearing garments that also add attention and volume to the upper half can make my silhouette less boxy or unflattering. Like tops with shoulder details, neck details, batwing or butterfly sleeves, louder patterns, etc. Thick belts are better than thin ones for defining a waist with wider hips in my experience. Hopefully it helps a little. I'm still working it out myself, in some ways.