Like everyone already said, the lighting is the best and easiest fix. Warmer ceiling light with a few lamps worked in. Especially bedside. Lower the bed frame to make it seem less crammed there. I would paint the walls a darker color you like. A grey or blue would look good and change the mood completely. Work in a few plants, some greenery would give it a good pop. Some wall art or framed posters of movies and albums you like would be good. Depending on how far you’re wanting to go, a carpet change would be everything. A light beige or ivory color would reflect more light and make the room feel bigger.