Communication is the key for a good relationship with the contractor you choose. Contractors love sketches, pictures, layouts, written summaries, computer aided visuals, or anything that you can give them that will make the job easier for them to visualize. Decide what type of contractor is best suited to perform your job. Begin making your calls or sending e-mails to set up appointments with prospective contractors.
First impressions are extremely important on both sides.
Articulately communicate to the contractor exactly what it is that you want done. Show him any paperwork and visuals you've accumulated. Asking good questions during the meeting is extremely important. Ask questions about the warranty- what does it cover and most importantly what items are excluded. Any major project should have a blue print and a floor plan or sketches detailing what the finished job will look like.