Follow the rules. The rules being "make sure you don't break any laws that could be considered a felony in the state in which your cult resides."
Think about it...The Branch Davidians had issues because they were stockpiling weapons (some of which were illegal), and the Yearning of Zion Sect has issues because of sex with children (which is illegal--duh).
You know, you really got to be more under the radar...like the Amish...or the Mormons. see note
Note: These aren't cults... Anymore.
Also, I've just decided that polygamy is like a republican version of swinging.