I came to this one via skeptico. I loved the insights on waiting rooms and avoiding insurance compensation (dentists, who are clearly not quacks, have been lucky to avoid the insurance quagmire that trapped physicians). The only recommendation I'd add is to avoid therapies that have obvious toxic side-effects. Never use a herbal remedy that actually has noticeable activity. Don't do chiropracty on the neck.
Overall a wonderful guide to success in quackery: A Photon in the Darkness: How to Succeed at Quackery (Without Even Trying). There are lessons aplenty there.