You should give a read-through of the Personal Trainer’s Thread, too. Some good info got put up in there from other trainers. Feel free to bump it with more specific questions.
Another avenue toward this is to find local rec leagues (softball, basketball, dodgeball, whatever) and offer to do seminars about S&C, injury prevention, nutrition, etc. When I got into working with paintball athletes, I contacted a few local fields and did a quick little presentation. It definitely helped a bit.
A paraphrased quote from Alwyn Cosgrove on this (who, as you should know, is The Man for setting up a fitness business): Would you be comfortable charging $1 per hour for your services? Of course not. Would you be comfortable charging $1,000 per hour for your services? Of course not. So the key is finding the point in between where you believe you’re providing an appropriate service at an appropriate rate.