I, personally, use floor plans when I being a build. I love working off actual floor plans so I get a better realistic layout and flow to my builds. From there I start with the walls and rooms one the main floor, then the second, then I add the roof to complete the basic shell. From there I go on to the windows, doors and siding, and begin the layout for the exterior landscaping and design. Then I do the furniture and much of the decorating. Lately, I have been leaving the flooring and wall colours to the end, so I have an idea of the colour scheme of the rooms. Not all floor flatter certain furniture or wall decor, so I leave that to the end.