1) Use the most common gesture in the world
The "eyebrow flash" is the most common gesture in the world. Even in cultures where it didn't evolve as part of their society, they've learned that much of the rest of the world instinctively gives this gesture on meeting people for the first time.
It's a fairly simple gesture - raise your eyebrows and make your eyes wider!
This gives people the impression that you've "seen" them, that you recognise their presence. It makes them feel a sense of importance in your world.
It's so effective that people will wait in line 7 minutes longer, on average, if the person they're waiting for gives them this simple gesture of recognition!
2) Use a smile
You smile with your teeth. Anything less gives whoever's on the receiving end the sense that the attempt at a smile is insincere. This is the "primate play face" and it's one of the deepest instincts we have.
3) Handshake the right way
A handshake can convey an astoundingly complex array of meanings. If you want to create the right first impression with a handshake, it's a good idea to match your opposite number with your palm straight and vertical, and responding with the same firmness of grip.
If the other person gives you a softer shake than yours, back off to match it. It will make that person more comfortable.
If they give you a firmer squeeze that you, increase your firmness to match. It will make you appear more confident.
This last one is particularly important for women, who have often been on the receiving end of handshakes intended to intimidate.