Firstly, ask yourself do you really need to be there? Setting up an office in the US is time consuming and costly. If you do decide to set up shop there are a few things you’re going to need:

1. A US company. We used Orrick Corporate Lawyers in London to set this up. We’re incorporated in Delaware with a license to trade in California.
2. A visa. There are a ton of options for entrepreneurs including the L-1, E-2 and O-1. Use a specialist immigration lawyer to assist with your application. Recommendations include Goeschl Law Corporation, Dunbar Harder,  and The Wright Law Firm . Be warned – visas are time consuming and expensive to obtain.
3. Payroll, healthcare and a pension plan. There are a ton of providers for each but we used a company called HSP who will act as a broker / intermediary for each.