Most small businesses in New York start as a limited liability company, which keeps your personal assets separate from the business's debts. You form one by filing Articles of Organization with the New York Department of State, which can be done online.

New York has a requirement that surprises many founders: within 120 days of forming an LLC, you must publish a notice about it in two newspapers, chosen by the county clerk, once a week for six weeks. In Manhattan and some other counties this can be expensive, so budget for it early.

Once the notices have run, you file a Certificate of Publication with the Department of State. Skipping this step can suspend your LLC's authority to do business in the state.

You'll also want a federal Employer Identification Number from the IRS, which is free, plus any city or state licenses your industry needs. The NYC Business Portal is a good starting point to see what applies to you.

Fees, rules and forms change from time to time, so always check the Department of State's website, and consider an accountant or attorney for anything complex.