Call the better business bureau to find out where to obtain information from the state you reside in to ensure legal requirements are met & it may be prudent to consult an attorney, all legal firms are supposed to provide pro Bono consultation monthly & call to ensure the attorney is providing correct information. The state Capitol where you want to work will direct you as to legal requirments.
Many successful companies began in someones basement and/or garage. So as long as you have the proper tools and equipment along with your own artistic talent you are half way to being a success. Most important now is to have only safe&clean materials to work with. This should be your highest priority. And customers(start w/friends&family)will notice this priority and will want to show off not only the art of the tattoo but will confidently validate your work as being on a professional level. Before you know it it will spread by word of mouth, until one day you will need to open your own shop. Good Luck to you.