Read the script. Identify and underline every mention in the script about the barn scene. Specific mentions in the script are called "given circumstances." Make notes of all given circumstances and fresh ideas you have for the scene.
Discuss the scene with the director, prop master and costume designer. Ask the director if he plans to stick with all of the given circumstances in the script or if he has ideas of his own. Heed all adjustments and ideas the director gives you -- your job is to bring the director's vision of the scene to life. Compare notes with the prop master and costume designer and make specific requests to ensure your scene is filled with every prop and wardrobe requirement it needs.
Draw an outline. Chart out the barn scene on paper. Plot scene requirements -- barn and fence lines, for example -- and note dimensions of each physical property. Incorporate all of the director's notes in your outline. Be as detailed and specific as possible before moving on to Step 4.
Assign a set building crew. Nominate leaders -- physical construction and paint leaders, for instance -- to oversee individual steps of the set-building process. Discuss the scene and hand out outlines to all set crew leaders. Answer and clarify any questions before construction begins.
Construct the main body of the set. Build a barn facade, for example. Construct two sides of the barn -- the front and the left side, for instance -- and rotate the sides so the front is off-center. Positioning the barn off-center, at an angle, gives the illusion the barn has all four sides. Build a windmill, for instance. Cut out windmill fan plates and spray all sides with metallic spray paint, again giving the illusion the windmill fan is constructed of heavy metal.
Paint the set. Save money and time by painting only those sides visible to the audience. Paint only the downstage side (front side) of a fence row, for instance -- the side facing the audience.
Add details. Place hay bails outside the doors of the barn. Spread hay on the stage floor to create a farmland illusion. Chip the paint on door and window frames to give the barn a weathered look. Tie twine or wire around fence posts to give the impression of shoddy repairs. Attach door handles and locks and place shovels -- and other farm equipment -- in a position where they are visible to the audience.
Make adjustments to the set, as necessary, as rehearsals progress. Keep spare paint and lumber on hand in the event set pieces break or require quick repair.