When a room feels stale, or your design is just not working, I like to try something as simple as playing with the layout. Right then and there, start moving the big pieces—chairs, rug, sofa, table—around. It's like a puzzle, and if you experiment and take your time with it you will find the right fit.
Maybe all you need to do in that room is change your perspective. And give yourself something good to look at. Move a chair so it's facing the fireplace. Turn your desk so you have a view into the backyard.
And when you're really stuck, step away from the room. Completely.
Go outside. To your own backyard or to somewhere far away.
Get yourself a new view. Change your perspective, not just your furniture. As Julia Roberts (as Elizabeth Gilbert) says in Eat, Pray, Love, "marvel at something."
You'll come back refreshed, with a fresh eye, and ready to make a change.