1. Hanging art too low or too high — Hang art so that the horizon line of the artwork (1/3 down) is 5 feet 6 inches from the floor, which is approximately eye level for a typical height person.
2. Out of proportion — Decorative objects should be scaled to the size of the bookshelf, mantel, end table, etc. For example, one or two appropriately sized vases are better than multiple small vases.
3. Rug size too small for dining table — The chairs should have all four feet on the area rug when diners are seated. A good rule of thumb is 30 inches to 36 inches from the edge of the table.
4. Unbalanced accent colors — In order to carry a consistent color theme, the pop of color should be used in three instances—too many and it will dominate the room, too few and it will go unnoticed.
5. Choosing the wrong focal wall— Every room you walk into has a focus or point of view that you naturally gravitate towards. Positioning the furniture in that direction, painting the wall, or hanging eye-catching art will pull the room together. If you select the wrong wall, it will feel "off".