1) Simple tiles or finishings
Keep the colours light and design simple, most bathrooms are not gigantic and this will keep the room feeling spacious.
2) Carefully thought out layout
Layout makes a lot of difference as it can make a smal space more efficient. If needed get a professional opinion for the best layout. make sure there is enough storage space and enough space to move around freely.
3) Great lighting
Whether you have a naturally well lit bathroom or not, artificial lighting will make a big difference to the comfort of the room. Make sure you have a central light as well as one above or integrated in the mirror.
3) Colour coordinated towels and accessories
Look in magazines and online to see what colour towels and accessories would suit the colours of your bathroom. These elements should go well together and create a pleasant feeling.
4) Free from clutter
Although there will occasionally be some clutter in the bathrom, try to plan storage spaces and keep supplies to a minimum. Keeping surfaces bare will make the bathroom easier to clean and the space more pleasant to look at.