I have two questions: Im starting a Talent Agency

Do you have to have a business license to start a Talent Agency?
How do you meet top casting directors and producers to book jobs for clients?

Of course you must have a business license to operate a business. And second, the best way would be to actually take a job at a talent agency and see just how the business is run. What better way to learn than every day for 8 hours and get paid for it? That's what I would do. Any other way is going to cost you a lot of money for your mistakes. Also, this way you can see just how these talent agency folks meet the directors and the producers.

You need lawyers to take care of any contract and you need a lot of money up front so get the lawyer now and he will answer all your questions.