Windows, doors and overall wall dimensions:
It is helpful to label each walls directional location (ie. North, South). Include the width of any doors, windows, base or ceiling trim in the room. If the molding is detailed please include a photo so I can attempt to recreate it.
For archways you will need to include the overall height and width of the entry. The height at the point which the curve starts is also important and don't forget to list the location on the wall itself.
The above example illustrates how to correctly measure multiple windows. It is important to measure from the actual window opening to window opening and not from the outer window trim to trim. Since we are measuring for the location of the window on the wall and the window trim is attached to the wall and not a part of the window itself, it's important to start and end measurements in the correct locations.
Any permanent fixtures such as fireplaces, built-ins etc.. please include the location on the wall and the overall dimensions of the item.