Paint the ceiling a lighter color than the walls. This will make it seem higher. The color can be white or a lighter shade of your wall color.
For consistency, paint the trim the same color as the rest of the house. If this is white then paint it white. If you want a more mono-toned look for your bathroom you could paint the trim the same color as the ceiling. It would still be a contrasting color, just in the same family as the wall color.