When you moved into your current home, you likely laid out the furniture pretty quickly. You probably hung up some things on your walls pretty fast, too, based on the layout of the room. However, did you wind up with any gaps that could use something there? Knowing ideas for how to fill in the empty spaces on your walls brings more life to them.
Shelving
Floating shelves add vertical intrigue to a room. You can fill them with decorative pieces to accent the current aesthetic, or you can actually use them to store books, DVDs, and things you don't want kids or pets getting in touch with. They can certainly free up valuable counter and table space throughout the rest of the room.
Function
Your empty wall space doesn't have to be filled artistically. You can add a huge wall clock so everyone always knows what time it is, or you can put up a message board or calendar so everyone can keep up with everything. Wall sconces can add diverse illumination to your room on top of or in lieu of other lamps and sources of lighting around the space.
Paintings
You don't have to visit a high-end art gallery to find fine paintings, nor do you have to restrict yourself to the mass reprintings everyone else can get at home decor stores or big-box retailers. If you buy fine paintings online, it lets you search the world for the specific artists, styles, sizes, and imagery you want within the budget you're willing to spend. Buy from anywhere, and have it shipped to your front door.
Mirrors
When you're already content with how a room looks, a mirror is often the way to go. It can reflect the colors and visual aesthetics of a room to reinforce them, but it can also reflect light to make any space feel bigger. In a living room, put some kind of seating in front of it. Mirrors also pair well with dressers and vanities in bedrooms.
Blank spaces on walls can stand out pretty obvious to anyone in a room. Whether they're standing or sitting, empty wall spaces will be either at their eye level or easy to look up to. Fill these spaces with things that are beautiful, comfortable, or just utilitarian in nature. All these aspects improve a home.