First, I suggest contacting to several different moving companies for quotes. This will enable you to make comparisons and allow you to get the best rate.
Keep in mind many companies will do the packing for you which can take a lot of heavy lifting off your plate.
Put a color coding coding system in place and be present while packing is going on. This will be quite helpful to the moving company when they are unloading boxes because they will put them in the appropriate rooms.