Determine the perimeter of the room you're designing. Use the ruler to draw this shape on your paper. This is your boundary line.
Determine placement for the closet doors and entry door. Doors should generally be sized between 30 and 32 inches wide.
Determine placement for the closet storage area. In general, closets should be at least 2-feet deep and between 3 and 4 feet wide.
Determine size and placement for windows and draw them into the boundary lines.
List the furniture that will be included in the room. This generally includes a bed and dresser, and maybe a night stand or desk and chair. Measure each and place them where appropriate inside the boundary lines. Consider window and door location when laying out furniture.