1. Stick with a white or neutral color palette - from the walls and floors right down to the fixtures and shower curtain.
2. Swap out a standard door for a sliding pocket door. A standard door can take up valuable floor space with the door swing. A pocket door simply recesses into the wall for added space.
3. Let the light shine in! Natural light is a great and inexpensive way to illuminate a space. If you're short on windows, add both ceiling mounted fixtures as well as wall sconces to keep the space as light as possible and less cramped.
4. Remove that chunky vanity and increase surrounding space with a pedestal sink. Just make sure you have enough storage elsewhere.
5. The use of smoke, I mean, glass and mirrors... The use of clear glass makes spaces appear larger because of the obvious; it's see through. Glass shower surrounds let you view the entire room, and glass shelving seems like its contents are floating on air. The use of larger vanity mirrors distort the proportions of the room, making the space appear wider than it is.
6. De-clutter! Only keep essentials, especially in a powder room, in plain sight (ie. hand towels, soap, and extra toilet tissue).