There doesn't appear to be sufficient space for stack on the windows near the TV. I recommend inset Roman shades there. For behind the sofa, Romans under curtain panels. you can coordinate your choices for a seamless look.

What Beverly shows you works well and looks terrific to start. The only thing I would change is the TV - change it to what katinparadise and rthawk described. The console your TV is on now is contributing to the visual clutter - and their solution will eliminate that and clear up that corner area. Your room looks so much better with the sectional moved to the long wall. That sofa table Bevs shows really works with that end of the sofa - so you can add a lamp and make the room even more cozy. I love the curtains Bev shows and the way to hang them so they don't crowd the window (high) and full. Good luck, have fun with your new room! You are on the right track OP.

The problem in your room is the terrible quality of like from that fan light. Turn it off and NEVER TURN IN ON AGAIN. I would take advantage of the lamps you have on your mantel and the piano. See if there is space for a small floor lamp next to the leather chair in the corner. Consider fishing the electrical cord under the rug to activate small floor lamps that can be placed next to your sofa. This floor lamp slides under the edge of seating to be very minimal in the room. https://www.crateandbarrel.com/clare-antiqued-bronze-floor-lamp/s406236 Replace the fan with a ceiling fixture. Consider changing the color of your rug on the floor.

Does the sectional fit comfortably in the room? It looks fine, but sectionals can create layout problems when working with a small room (which yours looks to be from the photos). A floorplan of the room with measurements and the measurements of the sectional (or a link) would help on that front. Are you able to take a photo of the sectional in the room? That is the other thing that would help us assess whether it works or not. When I see people complain that their room isn't cozy, it's often because they have skipped over coffee and end table and table and floor lamps. The absence of these makes a room seem stark and unwelcoming.