What tricks do you use to tell if person is good or not !?

In some situations you need to know or at least ROUGHLY know, what's your opponents strength is, so besides just asking boring : what's your rating? What tricks do you use to guess their playing strength?

I usually ask : if after e4 someone response with d6 , what's that?  If they can tell it's pirc defence, they might be pretty good and definitely not a novice player.

I don't know, I don't know... if someone knows, then what?  Their rating could be anything from 1000 - 3000 .  Not really a good way to estimate someone's playing abilities.

That's good enough, or even if they just know Mark Dvoretsky I think it's already not a beginner strength.

Not like post #2 about Bobby Fischer - it's like everyone knows him , just like Kasparov even old lady will know them , doesn't mean they can play chess. But Mark Dvoretsky is not so official and I think only people who are in to chess will know him .

Any way good answer.

What? 

Especially if you encounter some chess hustler and money is at stake, you need to be smart about it and not just ask for his rating (he might lie or give some random)