Add An Accent Wall
If you've got a bare wall in a room, you could turn it into an accent wall that completely changes the character and feel of the space.
Accent or feature walls can work well in highly visible spaces to serve as a grounding point for a design theme you're trying to communicate in your home. For example, if you're trying to create a "rustic" feel in your space, you might consider using barn board tile or natural stone to spruce up the area. Or, if modern is your preference, you could consider using glass tile or porcelain, or even some combination of materials to beautify the space.
An accent wall doesn't even necessarily need to be a standalone wall that is separate from everything else. You can effectively integrate these design features into spaces like shower stalls, bathrooms, or floors. With the materials now available, the permutations are seemingly limitless and also help differentiate your home. Back when everybody had the same square floor tiles it may have seemed like the only option was to have yours installed in a diagonal pattern, but those days are long gone!
Next time you're walking up or down your stairs, or staring at your tv screen, think about how an accent wall would dramatically change the space.