Plants. There is probably a bare corner of your kitchen ceiling that could benefit from a hanging plant. Plants can soften up the corners of a room, as well as adding some visual interest. You can use real plants, but if the plant is going to be in a hard to reach place, you can find realistic looking silk plants.

Paint the walls. Instead of plain white, or dark, rich colors, choose a neutral color, like grey or beige. Neutral colors won't date the room, and won't create a clashing palette of colors.

Another suggestion for brightening up your kitchen is through the use of mirrors to capture the sunlight and bounce it across the room. For the most light distribution, place a mirror across from a window or on a wall that corners against the window wall.