I would definitely add colorful shoes and I like the idea of chunky bracelets, like the model has. I don't know about a belt. In lieu of chunky bracelets, you could also do a giant cocktail ring.
You could do a bright skinny belt! A skinny wrap belt would be cute, too. Gap/ banana had some recently. I think colorful bracelets would be perfect. Cute dress!
I think some colorful shoes, maybe some strappy sandals, some colorful bangles and a a bright clutch. I probably wouldn't do a belt at all with this one but that's just my preference. I'm sure it would still look cute. I'm a minimalist though, I would probably end up with a metallic strappy heel, some silver bangles and maybe a metallic clutch. Not colorful I know but I'm like that.