The best way to find someone's weakness is to manipulate them through specific questioning. How their answers are expressed (they may or may not use a defense mechanism), what they say and what they don't say can all be very revealing.
You can also discover people's weaknesses through observation - body language can reveal a lot about someone.
After the weakness has been discovered, it's easy to exploit.
I don't try to search out people's weaknesses.
If a person I like tells me something that bothers them, I try to respect it.
If I'm antagonistic toward a person, I don't look for their weaknesses. I'll talk, I'll say what I want, and I'll keep my eyes open and hear what they say. Instead of trying to push my point, I absorb theirs and respond like casual.
When I have enough information to put it together, I'll push the point.
Honestly I don't need to find people's weaknesses, that's the beginning part, to wear them down. If my point stands alone, it wins. If it doesn't, manipulating weakness won't help it.
basically what tk said. its an interogation game, paying attention to where others place value and emphasis. if you can see what makes someone pause, thats usually a nervepoint for them, paying attention to the things they are conveyed unconsciously IRL such as body language is key, as is tone, pausing, inflection, and rate of speech. our bodies are more likely to betray us than our words. the internet is a bad example because people have time to take pause and give thought, people that rush themselves still give things away.
being able to note where someone omits truth can be quite telling also. so being able to see through other peoples smoke and see things as they truly are is critical. if you understand human nature and play the statistics you can usually come off as knowing more than you do, and this makes people nervous and more likely to admit the truth, if they think you already know, then they need less energy to tell the truth.
and never forget the primary rule when dealing with people "we are moldable not static" in many cases we can project ourselves onto others, and influence their subjective reality with our own. so even if something isnt true, many times we can make it true, if our version of reality is more persuasive than theirs... this catharsis concept is something very few understand... and is EXTREMELY powerful...
The easiest way is to become friendly with someone and slowly learn everything about them. The most people that I have known 5+ years I can play like a fiddle.
This isn't very quick but it is the most effective. You can only do this with people that you don't mind hanging around with for such a span of time, obviously. You won't reach any specific goals but those people can be used to satisfy current needs like borrowing money.
It depends on the weakness and what one hopes to achieve from it.
For example: Ted Bundy knew women would trust him more if he had an injury. So he pretended to have an injured arm (wore an arm sling), making himself appear more vulnerable than he really was. This worked very effectively in luring unsuspecting prey.
You find weaknesses by observing how they react in certain situations. So yeah, pushing random bottoms is one way to do it. Other is comparing their emotional states in the long run.
I distrust everything people say, but it is obvious they are ashamed of something if they change their tone. It is difficult for someone to admit a weakness to someone else without sugar-coating it. If anything, they'd sound defensive if they confessed to having a weakness and break character. :p
If I find a weakness, now I know where not to press. You should be wary of whom you confide in.
That's kind of sneaky to use time in your advantage like that. I'll make a note to that, though I'm not entirely sure what it means to really practice it. The theory seems sneaky and all to clever.
You are way more clever than you give yourself credit for, seriously. How can you live with mistrusting every person you meet? I'd feel so alone if I did.
I think sugar-coating should be mandatory at all times.
It's easy to trust in those who gives good advice. Maybe I should look into that trust some more.
It is actually less suspicious to provoke in the long run. If you push buttons like crazy, they are more likely to build a wall against you, and if they are adamant it will be almost impossible to get anything from them.
I am alone, always been. I don't feel alone, though. Plus, I got the internetz and you. :p
And yes, people giving good advice have better chances to attract less experienced victims.