First off, great job on the mantle and area rug ( size). Instead of plain blue, why not introduce some turquoise into your room. I can't tell if that club chair in the corner is dark blue or black. If it's black, I'd remove the ( comfy but not so lovely) round chair from the room and place the club chair in that corner. Add some fun turquoise pillows , some roman shades for the windows and get an ottoman for extra seating and to use as a coffee table. You would get more light in the room if the walls were all the lighter color. You could use some pictures ( one on each side) of the mantle to add color .

This one at Wayfair