1. Don't come across as arrogant or a jerk. Be civil. Try to be as reasonable as you can.

2. Recognize that when you're on somebody else's property, you have to play by their rules. (On public property, you should be able to claim some rights to do certain things, but see rule #1.)

I have only once had a problem when following these two rules. (Got thrown off a ranch on Sherman Hill, which we didn't know there was even an issue because we got onto it without passing a "no tresspassing" sign by coming in off a railroad access road.) I've been asked to leave private property other times, but only the once have I been hassled, yelled at, or verbally abused.