Here are some simple decorating methods to help brighten up a room.
Since you can always just place a window in a room, replacing natural light with superficial light is another way to brighten it up. You can help balance your lighting with floor lamps that will help evenly distribute illumination. Having lamps with dimmer switches can easily change the ambiance as well.
You should make sure that the room has an assortment of lighting types. This includes overhead lighting (recessed fixtures, pendants and chandeliers), task lighting (desk lamps, art lighting and table lamps) and accent lighting (sconces and under-cabinet lighting). These types of lighting will help layer the space and not overwhelm it with brightness.
You can always bounce more light off of any reflective pieces so why not go for the decorative ones! Vintage mirrors or mosaic mirrors are beautiful home accessories that will help create focal points in your home while brightening up the room by reflecting the light from you lamps.
Try places a mirror directly across the wall from your window. Even add a drape over the mirror to help give it the window like effect. This window mimicking will give the illusions for a second window while bringing more light into the room.
When choosing a color to paint your walls lighter neutrals such as warm white, dove gray or light taupe will make a space appear more open and airy. You don’t have to just paint your walls to create this effect; you can also paint your ceiling or moldings.
Use paint with sheen. Painting in a flat, matte or satin finishes will soak up light, while semi-gloss, high-gloss and lacquer finishes tend to reflect light.