Love the mirror you have picked out. Where are you planning to hang it? Looks like it is tall and narrow. It might be the right size to put on the wall going down the hallway to the right side of your TV wall. Or hang it over the desk. You could try it horizontally or vertically.

You have a nice clean space. If you are planning to replace your coffee table you might look for something round or square, perhaps glass and metal. Pull the coffee table out a bit from the sofa and add 2 arm chairs opposite the sofa. If you get swiveling chairs they will also be convenient for watching TV.

A console table on the long wall opposite the kitchen and large artwork over it.

Seems like a long room, so you could also pull the sofa out from the window and put a sofa table behind it. You could use a few decorative items, maybe a low plant and a lamp or two. Also, I know some people do not like carpet on top of carpet but I am not one of them. A smaller carpet on top of the one you have would be a good place to bring in some color (if you want color). If you are going for a monochromatic theme a geometric pattern would look nice. Maybe find the artwork you like first and then get the rug.

You have a great space. You only need a few touches to accent what you have now.

Send pics when finished. Would love to see it. Have fun.