I noticed when I looked at your profile that you are an ACE Certified Personal Trainer.
The American Council on Exercise has so many wonderful resources in order to assist personal trainers in building a personal training business.
One of the resources is the ACE Integrated Fitness Trainign Model. Within the model business aspects of fitness are addressed. As an ACE Certified professional you can listen to a webinar regarding the ACE IFT Model free of charge.
Too, I found particularly helpful a book that has been endorsed by the American Council on Exercise called “the Personal Trainer’s Business Survival Guide” written by Craig Mastrangelo. You might find that helpful.
Hope this is of assistance to you.