Agreed with myfavouritelucy! Don't be afraid of injecting an accent color you love. Things like curtains, pillows, and wall art can add a pop of color without being overwhelming. If you want to keep it calm, stick with some tones rather than tints. Those would be maroon, brick red, deep blue, etc. If you want more energy, some bright colors like teal, stark white, yellow (not too neon), etc... There are some great color schemes on pinterest!