Gaittec has a very good point. The problem with most academies is that they don't have the business acumen and experience to run a successful academy. Having a love for the sport is not nearly enough.
Over the years I've trained at: Ralph Gracie Academy
,Renzo Gracie Academy, Carlson Gracie Academy, Gracie Barra (Barra Tijuca), Gracie Barra Chicago, Roberto Maia Boston Brazilian Jiujitsu Academy,New Breed Academy (Evanston, IL), Sityodtong Muay Thai, Evanston Boxing Club, American Kickboxing Academy (San Jose, Ca)
Penisula Kickboxing (San Ramon, Ca??, and Gleason's (Brooklyn).
Each of these places has had relative degrees of success. Some of the best practices I've noticed include:
(1) Charasmatic leader and professional staff
(2) Academy feels more a like a home than a business, but the other can be true as well. But always cater to the the clientele.
(3) The use of contracts and direct deductions to keep students committed
(4) Seperate classes for beginners and advanced students
(5) Setting expectations for students. Let them know where they stand. For example, how long does it take to get promoted? Limits frustration.
(6) Handle problem students immedicately.
(7) Get feedback from students. What do they want to learn? Always ask them if they have questions?
(8) Don't forget about the kids and parents. Most schools target young males but kids and parents are a huge untapped market.
Like Kirik said, Tiger Schulman's Karate has had amazing success in growing their business. Also, West Coast Karate does monster business. You may not agree with their style but, from a business perspective, they have a lot to offer.
What are other best practices???