The proper body gestures.
Active listening – don’t repeat what other people say, don’t downplay other people’s feelings, don’t interrupt – just be a good listener and offer valuable advice. Even if you can’t, try to understand the other person’s perspective.
Don’t project a false image.
Deliver honest positives that don’t fall on the edge of flattery or sarcasm.
Don’t say general things in response like “Hey did you know that the atomic bomb killed X people?” “Well yeah its a war people always die.” Come on, offer a better response like “Wonder what would Japan be now if they bombed Tokyo instead…” or “Don’t think they had to drop 2 bombs in the end I think…”
If you’re going to talk about yourself, at least try to involve the other person. “Hey me and this friend of mine A, and friend of mine B, went to the casino yesterday and holy crap we won 5 straight rounds of bacarat and cashed out like $500! Natural FTW.” “Oh lol, well I haven’t gambled before (I’ve never met friend A and B either).” *awkward silence*