Social Engineering can be as natural as meeting a person.
You can take SE really far, but it's probably very easy for you to target people of your own culture, background, and local community. This is especially true if you would think about testing it out on people. Simply "getting to know someone" can yield tons of information that can apply to your trade.
Personally, I think a good SE will be a jack of all trades. What I mean by this is, they know enough about topics that are discussed in a particular group, but they are not necessarily a guru on the subject. Just being able to discuss a topic on level beyond just "hearing about" can open more doors for you.
Another good way to SE (This is very true with technology) is to be an "expert" on it. Sounding and acting like you know what you're talking about will gain confidence and trust (Trust is usually the goal). Young people who use computers can tell when a person is BSing about technology, but if you have a little passion behind what you are saying, you can talk over their heads to the point of them just accepting what you're telling them. Older people are similar.
But SE goes beyond what I talked about, WAY BEYOND.
If I had to give some tips based on personal experience (You don't even need to have any malicious intent):
Recognized the value of information- Being from America, I can tell you people, want attention, so much so they are a walking recorder willing to hit play on their personal lives.
Critical thinking- Many people don't do this. Their is a good chance many poster don't do this. Arguments are full of information (Emotions have a higher affect on people than facts). Being able to see both sides, play the devils advocate, and understanding peoples emotion will get you far.
Use what you know and if you don't know learn it - Here's an example. There is a kid in my IT class that is full of himself. He thinks he know everything about computers so much, he though his vast experience of 1 year, would out play the teachers 40+ years. If you recognize when you are intellectually out matched, you probably not going to win any SE schemes.
FYI, I am no expert, this is just personal experience. Here's a good experience for you, Stop watching mainstream TV, News, Website for a few month. Than try and watch them again and you'll see the absurdity of SE in action and the people around it buying into it. I no longer own a TV and avoid major websites and stick only with music. It a huge perspective change to pull yourself out of that barrage.