The first one is as a sole VA. This will allow you to take on a certain number of clients/hours and you are done. It will allow you to live with a set amount of money per week or month.
The other is to build a Team VA Firm. This will allow you to either partner with someone with skills different from you to broaden your services or just an extra hand to allow a growth in your client base.
We personally have opted NOT to take on any jobs that we were not skilled at doing. We felt that this allowed us the flexibility not to being tied to a particular person or being held ransom.