Measure any windows and doors in the room. Cut acoustic foam material to these dimensions with the utility knife to cover these areas completely, except for the door frame.
Cut enough corkboard with a utility knife to fit snugly into the window frames.
Attach the cut sections of acoustic foam for the windows to the corkboard sections with the foam adhesive. Place the corkboard sections into the windows to check the fit. Attach the remaining cut sections to the door with the adhesive.
Adhere acoustic foam material to all wall surfaces with the adhesive. Cut foam sections to fit around ducts and any electrical or plumbing conduits as needed, and attach with adhesive.
Lay out area rugs or carpeting to cover the entire floor surface. Cut the carpeting with the utility knife to fit around any floor vents.
Apply weatherstripping around the framing of all doors in the room. Open and close the doors to test for tightness of the fit.