Does your business have an EIN? If so, then you're already on your way.
If not, get one, and your business will begin to develop history under that acount & it keeps your business credit seperate from your personal.
Pay bills on time, setup phone, internet, etc, under the business name, and it'll acquire credit soon enough (6-12 months). Then you can get a secured credit card under the business name, and after that, another few months, you can get a regular one...or get an AMEX, as I think you can get those faster with less business credit history.
If you aren't as concerned about establishing seperate businesss credit OR leveraging your personal credit, you can do it faster, by using your personal SSN for the business purchases...but then the business is less seperate & harder to manage, etc, from a tax perspective (in my opinion).