Hold a color wheel against the green countertop. Choose two tones of green that lean toward the blue spectrum on the color wheel. Design your room decor around these colors.
Pour paint in one of your chosen colors into a paint pan, and paint the walls with a paint roller. Finish painting the wall edges near the ceiling and floor and the trim with a paintbrush. Let the paint dry completely. If desired, paint one accent wall in another of your chosen colors.
Create a tile backsplash or extend the current one with a row of tile in a color that complements both the walls and the green countertop. If the countertop is laminate and has light-toned flecks in it, for example, a cream-colored tile may help to neutralize the green color. Use tile mastic to adhere the tiles to the wall, and spacers to line them up perfectly. Choose a neutral grout color as well.
Hang curtains in the windows in a cream or light green shade, and tie them back with slightly darker green ties.
Add accessories to the room such as floor rugs, a tissue box holder, towels, trash can, utensil holders and pictures in the complementary colors you chose.