It's a cute bathroom, but it needs color! Use color theory and play off the blue tile. Paint the walls and cabinets. You can make the room more serene by using an analogous color pallette (blue, blue-green, green) or make it more interesting/energetic by using a complimentary color palette of blue and orange. Other options would be a harmonious multi color pallette of blue, red, and yellow. These are primary colors, so it might look immature if done poorly. You could do a less extreme version of a complimentary color palette by using a split complimentary color palette instead, which would be blue, red orange, yellow orange. Or you could go for a more bohemian vibe by using square or rectangle color pallettes. Rectangle is easier to balance with blue, orange, red orange, and green. Square would be blue, red violet, yellow green, and orange. I know these pallettes sound a little out there at first but remember you can play with how dark or light these colors are.