To the OP, I'm no expert on it, but have done research into it;
From what I have been told, there is no set rule for getting into this business. Besides the need for a CPL and IR! Obviously the more experience you have in a variety of aircraft the better, especially from an insurance point of view. I suspect most ferry companies would want you to have serious PIC time to join them, but that's not always the hard and fast rule. (Contact them and find out, if they like your face, you could get in!)
You can ferry anything from a Cessna 150 up to a 747 if you are experienced and appropriately rated in the aircraft. Ideally, you also need to be able to hold more than one license or be able to obtain a validation from some countries you may not hold a license for.
The key thing to consider before getting into ferry piloting is to make contacts. Like any form of small aviation business, its who you know that would lead you to a job. And once you are known to be professional, reliable, safe and a good person, you'll progress even further.
If you want to set up on your own as a freelance business, ontop of the basic business skills and preparation associated with any self employed business, you will still need some solid aviation contacts to supply you with aircraft to ferry (e.g aircraft sales brokers) or help you fly the aircraft on each ferry (other contract pilots).
Or if you are good at selling, you could try selling the aircraft you end up ferrying. Not simple or easy, but doable.
You also need to consider the risks associated with this type of flying, which is very challenging. You may sometimes fly over inhospitable places, or land in places with poor national security. The aircraft can be factory new or in second hand condition with suspect maintenance issues. You will be doing business with people you may not have met face to face, who could be pretty dodgy characters. You may get arrested or detained for simply not following local protocols or due to a communication error. Some places are well set up for aviation, while others are bare bone minimum when it comes to competence. You are the flight planner, inflight trouble shooter mechanic, pilot, impromptu diplomat and business man all at the same time!
As for the amount of experience, it all depends on what you want to ferry. The bigger the iron, the more experience you'll need to satisfy insurance requirements.
Also, its not normally a regular flying gig that pays a large amount. Some people ferry once every few days, some once a month, others once a year! It depends on how much you want to do it and which aircraft owners or sales brokers you know, that can give you a steady supply of work. The more you hustle, the more you fly.
Watching "Dangerous flights" is a good basic window into what you can expect.
Hope this helps. Like I said, I'm no expert, but did some research into it a while ago.