Will you be using or needing outside financing? If you will, you'll need a detailed business report. The sba
www.sba.gov is an excellent resource. It's not just about loans, there are templates for business plans, cash flow, profit and loss, etc.
In your business plan, use your opening page to reveal the passion of your company. This is your one shot at reaching the "heart" of your banker. Yes, they do have one.

The rest is nuts, bolts, and professional.
Getting vague now. lol. Contact your state commerce debt and local zoning to learn about any lic/permits/zoning you may be subject to. Even signs can be subject to zones and code. If it's food related, the health department. Tax id numbers for retail sales and use.
Anything specific you're not sure of how to proceed with? I know a lot of it feels like you're caught in horse/cart purgatory.
eta: This was our motto when we opened our company, got us out of more than a few pickles. LOL. "Sometimes it is better to beg forgiveness than to seek permission."
Katie