How to measure your room(s)
Using pencil, sketch out the existing layout (don’t worry about scale), and be sure to include the locations of all windows, doors, and closets.
Use a tape measure to measure each wall, corner to corner. record the sizes and locations of all openings and built-ins (doorways, pass-throughs, built-in bookcases, etc).
Then measure each wall in detail: start at one corner of the room, measure the distance from the corner to the outside edge of the window casing, from there to the opposite edge of the window casing, from there to the edge of a built-in cabinet, and so on to the opposite corner.
When you finish the first wall, total the measurement; it should match the first overall measurement. continue this process around the room, and note the measurements on your drawing.
Other stuff it would be helpful for us to know:
• ceiling height for each room
• location of all power outlets
• height of windows and doors
• location of windows on each wall
• location of any wall (sconce) or ceiling lights