New roof....eek....advice or tips?

material will cost about 95 to 110.00 per square for singles 7/16 osb with nails will be about $9.00 per sheet and it is good advice get the roof ready and have the shingles roof topped it is best to buy from a roofing supplier than a big box store and go to a rental store and rent a air compressor and nail guns makes the job go much faster