Denim, as in jeans? Tbh, I say stick with the white and denim theme. Too many colours and you will ruin the look. If you want it to look effortlessly stylish, don't add another colour.
anything really lol.... but i could see yellow jacket that stops at the ribs... maybe just the white and denim itself... it is summer so less clothes the better :D
I think red or purple would pop against the white and it would look cute
Red, Salmon, or pink. Those would be my favorite for that color combo.
I owuld say red and black
Anything neon (: