Start out as an intern or assistant at a talent agency. This will give you the chance to learn the business and see how talent can be effectively managed. Make sure that you try to soak up as much information as you can while you are there, and ask any questions that you might have.
Work to build contacts while you are working for someone else. You can utilize your employer's client base and industry connections to build a contact list of your own that will help you recruit your own clients in the future. Don't underestimate the power of networking, especially if you are employed at a reputable talent agency that carries a large amount of weight in the industry.
Make yourself official by starting your own company. You don't need to have any employees or even an office space, but if you are serious about becoming a successful talent manager you should spend the money to make your business official. You can start an LLC in most states for a small amount of money, and once you have your own business with an official name you can begin to create a brand around yourself that people will come to recognize and associate with results.
Promote yourself and your business while you try and obtain clients. Finding your first few clients to represent will be the hardest part of becoming a talent manager, but if you've done a good job of creating contacts and promoting yourself it won't be as hard as you think.
Do the best job that you can for your clients. Producing satisfied clients will help you to grow your business and obtain the most lucrative talent to represent in the future. Doing an outstanding job with your current clients is an excellent way to get word of mouth advertising and create larger client base.
Hire help as your talent business grows. You may get to a point where your success has brought you more work than you are able to handle by yourself, and at this point you can decide if you want to keep your business small or hire employees to grow it even more.