Today I was walking through the commons, and one of those pamphlet-weilding religious whacks was gonna offer me one of his tracts or whatever, but thought twice of it when he saw my black dress, eyeliner, fishnets, and knee-high Dr Martens. It was great- he turned to me, and started to offer his paper, thought twice of it, and kinda pulled back and pretended to be looking off in some other direction. He then tried to give one to Peter (a friend visiting from New Jersey), who was walking a few feet behind me and looking much less gothic. Peter pretended to be one of the enlightened, and the pestering summarily ceased.
So, in short:
(a) When asked “Have you accepted Jesus Christ as your personal savior”, say “I certainly have!”, in otherwords, be a wolf in sheep’s clothing.
(b) Look to be what a born-again would consider “Satanic”, in otherwords, be a wolf in goat’s clothing.
I don’t know whether metaphorically pretending to be other livestock works as well or not, but these two methods seem rather effective (with the caveat being that the latter method may make the braver zealots try harder, unless you are very intimidating; and that the former method makes you a lying bastard).