You have made a great career choice!
I have my certification through ACE and there are certainly plenty of materials available through your certifying agency and others who do business development.
The resource I have found most helpful, recently is a booklet called, “Everything You Need to Know to Start Your Own Personal Training Business” by celebrity trainer Chalene Johnson. She is the creator of workouts such as Turbo Jam and Turbo Fire and has been my trainer for my group fitness specialty formats.
It’s only 86 pages and available as a download, but she really breaks it down for you. You can buy it at http://www.turbokick.com/store/home.php?cat=38 for only $12.95. She is also doing a pre-convention seminar on Social Media for Fitness Professionals. Get in if you can!
I would also recommend going to the IDEA World Fitness Convention and the Personal Trainer Institute. That way you’ll be able to take workshops specific to building your business in many ways, including social media.
It may seem overwhelming at first, but remember, you only need that very first client and then you’ll be more confident. It’s not about convincing anyone but yourself!