1. Visa (are you here legally and are your workers)? There is a new "startup visa" and sometime in the future I hope to discuss it in more detail.
2. Financial law (what restrictions / rights do you have as a foreign investor)?
3. Business structure (what kind of business do you run)? This also affects ...
4. Taxation, which is always a concern.
There are several preliminary issues to consider before your business can even worry about the usual issues like costs, contracts, advertising, and the actual operation of the business: