U.S. Census Bureau (census.gov): A source for a variety of useful statistics, especially the Economic Census that comes out every 5 years.
"Plans are useless; planning is indispensable," according to Dwight D. Eisenhower, then Commander of the Allied Forces in Europe during WWII. Now, you may be in total agreement with the first part of that statement, but you are really not convinced of the truth of the second part.
There are lots of consultant services open to brand new start ups this short article highlights a number of the benefits associated with getting qualified suggestions as well as making the best use of these services.
Appendix - Resumes of principals/management; letters of recommendation from current business associates/customers/suppliers; marketing research data; demographic data; leases or contracts in place or as promised; business licenses; price lists from suppliers; trade or industry articles or data; floor plans; information on subcontractors; liability insurance policies.