Measure all doors the item must pass through when being delivered. Most upholstery items need a 31 inch door clearance. (a 32 inch door will barely give you this clearance with jams & hardware)
If your room is large enough, consider buying two sofas instead of a sofa and love seat. You will gain seating for one extra person and the price difference is not significant.
If at all possible, try to bring samples of carpet, drapes, and wall paint to match your seating upholstery. Once you have several fabrics picked out, we advise that you bring the fabric samples home to see them under lighting in the actual room where the furniture will be placed.
Most upholstery can be special ordered with the fabric of your choice, but there are a few which cannot. Special orders generally take as long as 5-7 weeks, with a limited few available in 2-3 weeks. Custom ordered upholstery usually changes the price as well.