We all have that pretty black dress that makes our bodies look skinnier. Avoid utilizing warm undertoned, and dark paint colors if you don't want to make your room look even smaller.
After selecting on a paint color for your small space, painting the walls and all of the trim will make the room feel larger. That means you should paint your window moldings, ceiling moldings, and floor moldings all the same color.
Use a few large pieces of furniture or accessories instead of multiple smaller pieces that clutter up a tiny room. That will also help the first step as well.