Use windows, centering furniture in front of them. Usually we strive to have the bed on another wall but in a small room, options can be limited, and it's often better to create a strong point with a bed than to awkwardly push it to one side. A bank of bay windows creates a natural nook for this bed, and the pretty window treatments give the illusion of a canopy.
If you are a fan of simple decor, try a white duvet with similarly hued furniture. To add a little pop, paint a focal wall the color of your choice. This accent color can be incorporated into the rest of the decor with throw pillows and blankets.
I like this. Center a rod attached to the ceiling and aligned with the middle of the mattress. Hang and drape a measurably long length of fabric into a canopy. It gives a tent effect. Kids love that. Plus, you can add and remove on a whim.