on what Chris said, and I want to re-iterate, the more time you spend as a Range Aide/Cone Kicker the better you will do during your RTP. I have quite a bit of adult learning and skills instruction experience from my scuba diving background (I am a divemaster) and it transferred over nicely to being a ridercoach. If I didn't have that I would have wanted a lot more time as a cone kicker. (I had about six weeks experience cone-kicking, but it was EVERY weekend) Your riding experience also helps, I had been riding for six years, and had been doing trackdays for a year, before I started cone-kicking.
One thing that Chris didn't really touch on, but I have no doubt he will agree with me on, is finding a good sponsor. You have got to find a school that you really feel comfortable with. You need to have good rapport with all the coaches and the owner/owners because you are all working as a team. If you're working for a school where you don't "Fit In" quite as well you wont learn as much. Ideally you should be able to consider everyone you work with a friend. I had a mentor/mother (I'm 25, she's actually a grandmother) at my school, she is one of the instructors and she really took me under her wing and taught me a LOT. If I didn't have that it would have been much more trying. She did such a good job that during my RTP the instructor thought I was already a coach and getting re-certified.
It is very fun and amazingly rewarding, Good Luck!