Ditto on the CPA. A good one will be well worth the $300 or so bux just to have him give you list of all the things you need.
On the other hand, you can check the web sites of the city you're in, the state you're in, the county you're in, the health department of the city, county and state you're in and the fed gov't, ergo, the IRS. It gets a bit complex but, as I said, a CPA can help a great deal. It's a bit daunting but usually the payoff is worth it if you're smart and don't try to figure all of this out yourself.
Oh, and keep track of everything. Write down every check and ever deposit you make in your check register and keep every receipt.
Have fun!
--Wag--