Here's what I know...
(1) He notices if you are nice to the waiter and he will like it if you are.
(2) He notices if you check your blackberry a half dozen times and/or takes unimportant calls during your time with him.
(3) He notices your energy- if you seem happy and if you have good, confident posture.
(4) He notices if you talk about yourself non-stop and never come up for air to ask about him.
(5) He notices if you are defensive about things in your life. If you feel particularly vulnerable or badly about the fact you lost your job, need to lose 15 pounds or have never been married, you need to come up with comfortable answers to those questions.
(6) He notices if you are fidgetting with your hair, looking around the room or picking your nails: these are all signs that you aren't really interested in him.
Don't forget to check out Yes, Man a funny dating movie!