To add to the excellent advice Grace gave:
~ Find at least one excellent instructor and take as many classes as you can from them. Approach one of them and ask if they would mentor you.
~ Go to conferences and workshops!
~ There are Internet sites such as http://www.turnstep.com where you can get ideas and help from experienced instructors.
~ Practice, practice, practice and practice some more. Find some buddies who will be your “guinea pigs” and give you feedback.
~ Some universities and clubs have instructor training programs – check for what is available in your area.
Best of luck!