How? New Rug? New Furniture? New paint color? New Lighting? New Window treatments?

Yes! New everything

Then I would find a rug you love and then the colors for walls, window treatments can come for the rug. I think it needs to be larger than what you have currently. What is your style? Right now you have traditional, modern & contemporary all in 1 room. If you are traditional then leave the chair rail and molding. If not remove it or paint it the same color as the walls to disappear. Paint the ceiling all 1 color. Paint the vents the wall color. The art should be hung closer together.

OR choose a fabric for window treatments and work from there.