How can i make my bedroom appear more light? its dark and i cant paint it.?

i will suggest you to change your curtain. Use a very light shade for your curtains. Using black out curtains can your problem of sleeping at day time. Use light colored bedsheets and comforters which will give your room a cooler and lighter look. You should use energy saver as they are good for saving energy and I personally think white light is much cooler than the yellow bulb light.