If your tween is a fan of featuring photos of his friends and family, make some modifications to these photos so they fit in with your blue-hued space. Create digital copies of each of the photos and, using a photo editing program, recolor the image, making it shades of blue instead of full color as it is now. Place these pictures in white or black frames to contrast with the color featured in each image. Hang the jazzed-up pictures on your tween's wall, or set them on his desk or dresser.
Make your tween's bedroom walls more attractive by adding a geometric border featuring shades of blue. Purchase or create a stencil featuring several geometric shapes. Using blues in several different shades, paint this stencil onto your tween's wall, using it to craft a border around the top of his room. Allow your tween to join in the fun as this decorative task is a relatively easy one that he may enjoy taking part in.
If your tween is forever in jeans, denim may be the ideal fabric to feature in his blue room. Purchase a denim bedspread to cover his bed in this sturdy fabric, or buy slipcovers featuring this fabric to cover a chair or sofa that he has in his room. To integrate the theme in a more crafty fashion, take some of his old jeans and turn them into throw pillows. Toss these additions onto his bed to add excitement and soften the space.
Select water as a naturally appropriate theme for your tween's blue room. Place a large aquarium along one wall, clearly establishing your water theme. Paint the walls in different shades of blue to make it look as if the room itself is submerged in water. Feature fish or other under-water creatures in the space to more fully establish this deep-sea theme.
If your tween has his head in the clouds, make the sky his room theme. Place a wallpaper featuring clouds on one wall, creating an accent wall to decorate the space. Select fabric additions in different shades of blue as well as white to reflect the colors present in the sky. Feature some other sky-themed objects, such as airplanes or hot-air balloons in the space as well.