Paint three walls a pristine white. Paint the fourth wall navy blue, and stencil in white polka dots. This will be your feature wall. Alternatively, use polka-dot wallpaper on that fourth wall. add navy blue and white polka dot wallpaper. On just one wall, the polka dots won't overpower the room. For a more dramatic look, consider painting all four walls navy and stenciling the fourth wall with medium-size white polka dots. To keep the look from becoming overbearing, paint the woodwork white and add white blinds or curtains.
Place a white occasional chair in the corner of the room, and add an assortment of navy blue and white pillows. Add a polka-dot pillow or two. You can also experiment with complementary patterns in navy and white, toile or fleur de lis, for example. Alternatively, throw in your accent color.
Add a blue duvet or comforter to the bed. Opt for a solid duvet or comforter, as it will allow you to swap out accessories. Pile on the polka dot pillows. This is another place to use complementary patterns and colors. For a final touch, add a throw in your complementary color.
Add stainless steel or brass knobs, pulls and accessories. The sheen of these materials will pull together your blue and white with a polished style. For a softer, more feminine look, consider wicker.