1) That they are competent and smart until they definitely prove otherwise to me.
2) That they are technical and interested in technology.
It's worked really well for me so far. In practice it means when I meet someone I say "You're a dev right?". Most people appreciate being assumed to be technical, and if they aren't we still get a great convo out of it. I admit it's kind of a silly thing, but so far in years of doing it I don't know of a time it's made anyone feel bad.
Edit - Also, if their answer to the dev question is that they are instead a product manager, UX, Designer, etc, I try and follow up with a funny compliment about their field. "Ah, so you make apps useable", etc. Again, just a simple conversational technique to make people feel valued.