Plant evergreen hedges along the length of the sides. The long, straight lines of the hut are ideal for a hedge row and hedges provide protection against harsh winter winds in a building that is traditionally short on insulation.
Paint each rib, or several sections of ribs, of the corrugated steel siding and roof a different color. The ribs provide a natural pattern to follow and by using a variety of colors the hut can take on an appearance that ranges from conservative to psychedelic.
Make the built-in "face" for the front of the hut into a real face. The door and two side windows, along with the natural half-circle shape of the front, combine to give two eyes and an obvious mouth to the building. Adding eyebrow, lips or lipstick, teeth and a pink "doorstep tongue" can convert your Quonset hut to resemble any person from a child to a senior citizen.
Splash bold colors along the lower insides of the hut with pictures or other wall hangings. This focuses the eyes away from the rounded top and takes away from the idea that you are standing or living in a soup can.