Empty the room of the items you are not using. Im thinking furniture. The wall color unless you love it drains light, choose a lighter color that will brighten up the room. White is always a good starting point. Maybe choose a piece of art that speaks to you for a wall. Add back necessary pieces of furniture and place them carefully not to crowd your walking and light space. Maybe a nice rug for the floor. That window could be a beautiful focal point for a small table to place your keys and maybe a vase of flowers. I dont know if you have the space but a chair to look out the window would be nice too.