There are a lot of visual tricks that can drastically change the appearance of a room with little effort or money.
Our first impressions of a room are influenced by space and light. So to make a room look spacious, even if it isn't a large room, we need to leave space around the furnishings. Furniture should be the right size in proportion to the room. For instance, over-sized high-back sofas will visually reduce the amount of space in the room.
Let the light shine in. The amount of light in a room affects the visual size of the room. It can look large or small depending on the light. Open curtains and drapes, and whenever possible, remove them.
In the photos below, the horizontal plane of the window valance gives the room more width. We need to give the room more HEIGHT. To let the viewer's eyes travel to the full height of the room and to let more light into the room, we removed the valance. Look at the difference ... quite drastic.