If you play cards, if you gamble you become sensitive to certain 'tells' and know how to play your cards.
Although using gambling tools to read general human behaviour might seem a bit discomforting, in reality, the person at that poker table who is 'reading' his opponents knows how to bet, as s/he has learned the behaviour of an opponent.
This gives one an enviable insight into human behaviour.
The player, who knows how to 'mask' his actual position in regards to the cards s/he holds, also possesses that 'power' to read people and how to manipulate them.
These abilities are not confined to that card table, of course, they are used in daily life by people who are aware of them.
A Few Simple Basics
Not to get into psycho-babble or over intellectualise, certain behaviours can be read and understood once one knows the 'tell'.
The 'Tell' is a giveaway action, mode of speech, behaviour. If a person who festoons his office with photographs of himself, awards and diplomas and acts as if a king in his domain, you know he has a crushing inferiority complex.
He uses these photos and awards to over compensate for his feelings of inferiority. So, you know how to play him.
Superiority Complex/Inferiority Complex
People who display overt signs of 'superiority' to others are over-compensating for a sense of inferiority.
They need the signs and symbols of success because they know they are not worthy.
Aware of their weakness, inability and general inferiority, they over react by attempting to prove they are 'better' than everyone else.
Most of these people are Bosses From Hell, men (or women) who 'Know' they are less than those who work for them, and attempt to 'prove' they are better by suppression and oppression.
Anyone who behaves as if they are 'better' than others has intense feelings of inferiority and uses this 'over compensation'.
To play them, act 'awed'. Let them talk and show off and be small to their giant in their presence.
You can play them like a piccolo.
There are people who will lie about anything and everything, no matter how unimportant. They have an innate fear of others. No matter how big they are, no matter how old, they lie.
Lying comes from fear.
This is a general fear, a cowardice. It is virtually genetic. They are afraid of everyone and everything and lie because they want to pick 'the best' answer in their limited purvey.
When working with someone whom you need to trust, you have to set a few 'traps' so as to expose them.
These can be monetary, but can also be general mistruths.
Many politicians are born liars. They will lie, deceive, misrepresent, and when caught try to 'explain' or twist, so that, in their own minds, they have 'escaped'.
Persons who try to be too precise are often liars.
A non-liar will say things like, "I believe it will take two weeks..." or "I will try to..."
A liar will say; "You'll get that in five days," or "I will..."
The fact of life is that you don't control it. You don't control the rain, the traffic, other people, or events. You can't be certain of anything, if you are honest.
The best you can do is express your belief and your intention and possibilities. To be too precise is dishonest.
The Use of Silence
Often, a person who doesn't say anything is overlooked. The assumption is that they have no opinion on the subject or, 'silence is consent'. In reality, people who are silent are showing a contempt.
Whether they aren't listening, whether they disagree but are not going to say it, there's a contempt as loud as farting in your face.
Too often people assume that because X didn't say anything s/he agrees with the point. More often, X is either totally against what you are saying and doesn't want to admit it, (like a spy capturing data) or has such contempt for you that anything that comes out of your mouth is flushed.
Anyone who is silent, "Hey where do you guys want to go?" and Jane says, "Movies!" and Sonia says, "Salsa!" and Tamika says, "Clubbing!" and Louise says nothing, one better keep their eye on Louise.
There are other tells where one can 'read' people. The few I've listed are quite obvious and will lead to you uncovering many more aspects you have never noticed before.
You'll realise that pompous guy is really a sorry mess who is playing the role of Great Man just as an actor is playing Superman.
You'll listen between the words to catch that liar who is seeking to deceive by behaving with such certainty in situations one can not be certain.
And sadly, you'll realise that the reason Louise is so quiet is because she has no respect for you or your ideas and is just 'there' for lack of elsewhere.