Room 1(Den)- something for windows- tall drapes.

Room 2(Dining)- decorative rug

I would add a coffee table and a couple coffee table books. I would not cover the windows, it is an important piece of art in that room. That's it. Less is more.
In the dining room the centerpiece is to big and too pizazz for the table. Replace with a smaller centerpiece , perhaps fresh flowers and lower the chandelier just a little.

Nice room! I think you need a prettier rug! You also need lamps/lighting. I'd lower the art to eye level, add a floor lamp by the sofa and a small table for between the two chairs. I'd also add accessories to the coffee table that relates to the vase on your console. Your furniture and room is super! I like this rug because I love the blue in your art above the console.