It's the details that pull the room together. Bromstad makes some jellyfish lampshades by stapling coffee filters and streamers together. The treasure chests become a feature by arranging them at different heights on platform boxes against the wall. Bromstad uses loop and hook tape to adhere plastic balls to the post; they look like bubbles floating up through the water. Paint contractor Danielle Hirsch creates depth in the room by using gradated color on the walls. It may sound intimidating, but it's really as easy as putting three colors on the wall and blending them with a dry brush. For the depths of the sea, Hirsch starts with the darkest color on the bottom third of the wall, then applies the next lighter color above that and then the lightest color at the top. The low ceiling is made cozier by painting it a darker color. If you want to make a low ceiling feel more open, paint it a lighter color than the walls.