Or you can make the house look like a tree house such as this one. Paint it with white and make accent colors pop up.
Another simple but beautiful IKEA Kura bed. Notice how they barely decorated the bed (except for the buntings) and just placed a mattress and added some soft and comfy pillows.
Natural wood finish will never go out of style. This classic design will always remain pleasing to the eyes, even in simple and modern bedrooms.