Internet filters, staring at the price ring-ups at the cashier instead of at the magazines, steering clear of midtown and generally trying to avoid known pritzus locales, and all-around being a hermit.
But no matter how much you try to protect yourself, something will always infiltrate your safegaurds and borders. Climbing Mt. Everest would work fine, but it’s hard to find kosher restaurants up there. So you have to know your priorities.