Overall decor is fine, perhaps add one accent color for some 'pop'.

When using a mirror always think about what is now double and waht you are reflection in this one is not worth doubling.. I would choose a color from the art work and paint the walls that colour and then add some color with the cushions . I can't tell if the wall beside the fireplace is a dark colour or if it is just in shadow. If it is neutral then I would add the colour to the fireplace jut out.An area rug with some texture would also be nice and I don't see end tables or lamps for lighting which would also add another element to the space.

Everything already said above plus curtains, if you like.

I would add media to area next to FP. With big 60" TV. Get a round coffee table in glass with metal. Z Galleries sells. Pick a accent color add that to pillows in various size and shape. Add tall unique items to coffee table. I would try sectional looking at windows float in room. By window 2 armless chairs in a bold print, using accent color. Pull into room not pushed against windows. Add panels to ends of windows, go darker than wall color. Under add dark bamboo shades. Roll 1/4 way dn. Home Depot, a Lowes sell.

Sorry thought it was sectional . But still move sofa as stated and put chair by window with a small dark wood table, add a big bass lamp in silver and a black shade to it.

This Is a fabulous living space. Changing thepainting above the fireplace could really add some pops of color. Also, simply changing your throw pillows to add color would give it a clean fresh look. Even if you really like black-and-white theme I would be a little bit more dramatic with it with the artwork and pillows. All those options are also pretty inexpensive.