I'm working on a book for which I came up with the idea in 2004. (I finally convinced a former professor to join me in writing it.) As part of the research, I'm interviewing quite a few successful people in the sports industry. I recently interviewed a classmate and he brought up a very good point that I think is worth writing about here, especially considering the emails I get asking how to break into the sports industry.
If you want to be a doctor or an accountant or a teacher, it's pretty clear what steps you need to take to get there. Even when you're in junior high or high school, you have an idea of what you need to do. At that same age, you may know that you enjoy sports and want to work in the sports industry, but what's the career path? The answer is that there's not one clear career path. There may be similarities, but there aren't any hard core specific paths.
My classmate's advice, and I agree with him, is to start early in volunteering. He talked about how he didn't do this, but wished he would have, and wished that someone would have given him that advice. He noted that it might have cut down on the number of internships (four) that he had to take before getting a permanent job. I can say that I was the same way in not doing as much work in sports early on as I could/should have. It didn't occur to either one of us and neither of us is sure why.
There is ALWAYS a sports organization that needs volunteer help. It could be a youth team, a university athletic department, a national or regional governing body, the local sports commission, a sports event that is coming to town, or any number of things. Interestingly, he has not been the only one to give this advice. Another associate in a prominent sports position mentioned that she advises young people with whom she speaks to volunteer with an organization or team in an athletic department that has nearly zero funding. This is a way to get experience, make your mark, and/or gain some resume credibility.
Even if the area where you're volunteering isn't an area that you think is your ultimate career dream, you'll still learn something from the experience. Seek out those opportunities and gradually take on more responsibilities as you feel comfortable. It will give you experience and also build up your personal network.