Measure the length and width of the room. Also measure the of length doors, windows and stairs or any other obstructions with how far each is from its respective corner. Write down the measurements on a piece of paper.
Determine your scale. For example, if your room is 5-by10-feet you may want to use one inch to represent each foot.
Draw the perimeter of your room to scale. In the example, this diagram would start with a 5-by-10-inch box.
Place the windows, doors, stairs and all other noted items in the diagram where they belong. Solid walls are represented by thick bold lines, windows by non-bold thick lines and doors with a gap in the walls with a line crossing from one edge of the wall to the opposite edge across the gap.
Arrange room items in the design based on the scaled-size. For example, a six-foot sofa needs six feet of unobstructed wall space, therefore it can not be in front the door opening. Place electronic items near plotted electrical outlets to reduce the number of cords around the room.
Make any adjustments with the items to see a few different designs based on different furniture pieces or electronic needs.