Always make sure to measure the space/area you're to put together your piece--. It is helpful to look around your surrounding area & things that can't be moved. Often, it might be helpful to use a measuring tape to precisely measure the space you have to keep your furniture.
Measure from the inside of your door. Be careful to note how wide your doors can open, and accommodate for doorknobs. If the doors can be removed, that might be a good idea to prevent damages.
Don't fail to measure the height &width of your stairways and bottom steps to the ceiling. Be sure to look after any sloped or curved surfaces.
Account for any low-hanging ceiling lamps or fans, breakable decorations that cannot be removed, stairway doors or turns, or angled ceilings or walls. Be sure to completely clear a path for your sofa.