>>647268Basically... Don't get caught. A large group of friends and I almost ran straight into a cop car, we ended up going flat against wall until he passed.
But if you do get caught, just try to explain how you wanted to take pictures (always bring a camera) say your a photography student or something. Act as innocent as possible and say you never saw any trespassing signs.
Don't dress too militaristic (no flecktarn, combat boots, or facemasks) don't carry any weapons or tools (no crowbars or knives or guns) or anything else illegal (drugs, beer, spraypaint)
If you're concerned about running into junkies or meth cooks or something get a small police flashlight. You'll need a flashlight anyways, and the police ones are blindingly bright and shock resistant so they can be used as clubs.
above all just use common sense
pic is from an urbex I did