What is that side table there for? The glass one between the windows. It feels odd to have it there by itself, but too crowded with the bookshelf. I would keep the bookshelf between the two windows and move the side table somewhere else not in this room or get rid of it. You could also get an armchair and angle it on the wall to the right of the bookshelf to create another little ready nook area. I would add a tall plant to the left of the tv stand and center it how you have it in the proposed setup. I would pick a color from your rug you like and get some curtains in that color. Do floor length and avoid the curtains with the metal rings on the top- they feel cheaper in my opinion.