Ran across this exercise from Ed Hooks. Pick a profession like Dr. or used car salesmen. Then act out a little scene where you as the character are waiting at a bus stop, not saying anything. It is impressive how the audience can guess what your job is from just how you're standing there.
You gotta figure this stuff out from the inside. Easier to come from the inside and become the character, then to come from the outside and try and analyze why that contra posta pose with a slight head tilt is suggesting party girl to me. Listen to Obi-Wan "your eyes can deceive you [distracted by irrelevant details] stretch out with your feelings."
have I mentioned a character's zero before? The neutral pose someone naturally returns to. How their body fits most comfortably in space when there's not something else happening.
So if you can find this feeling of what it is to be a Dr. or whatever, and if you can put it into your character. Then you have to try to get it in there on every frame of the scene, so not just start the scene in character pose and then go and do whatever generically, no she has to walk like a dr. talk like a dr. brush her teeth like a dr. etc. Easy peasy right?