Business lunch
When having a lunch with your client or business partner, order the same (or similar) as they. You can also use the phrase "that sounds good I will have that too". You share the same interest and you have something in common.

Spark interest
When you’re talking to someone you’re interested in or on a first date with, you want to subtly match their movements.
If she gestures with her hands when she talks, make similar gestures when you talk.

You’re not trying to play “Man in the Mirror”, you’re just consciously making very small adjustments that put the two of you in sync in ways that people do unconsciously all the time.
You don’t need to be exact, just close.