I seem to be a natural flirt.
It is just a little bit of cheekyness, bit of risky innuendo, mixed with making someone centre of attention, little compliments, being a little bold, being slightly familiar, having a little giggle at someways silly ways but not mocking, more like delight in their odd bits. Dunno. I do it with everyone, I don't really think about it much. It is not something I decide to turn on, just happens when I am feeling good. I guess flirting is just making someone feel flattered and special by your attention. It does not have to have any sexual connotations. I suspect body language is really important but I don't pay much attention to mine - maybe plenty of eye contact, leaning in to create your own intimate space in a crowd, smiling, being a good listener, shutting out other distractions. I've been known to bat my eyes a little, but in such a way that it is obviously put on for them, but people love that stuff. It is like a little in joke. I tend not to touch people even though I like being touched myself. I'm definitly a hands off flirter. But I hear a hand on say the arm does wonders - make sure they are drawn in first otherwise you might be seen as invading personal space.
Sometimes I will make up outragous stories about someone to other people right in front of them, like how they have this awsome tatoo on their behind..Somehow I am believable..and people wonder how I have seen it and everyone starts imagining..all in good natured fun.
One cheesy example I remember, because someone pointed it out, I was doing some presentations around my organisation and there was this young woman in the audience who I thought looked familiar and might have been at an earlier presentation. So I asked her in front of everyone, and chatted about how she has a double, and I finished by saying "Don't worry, she was good looking". I like to flirt with an audience.
It does not seem to occur with people I have no connection with. You have to get something reflected back for it to work - kind of a feedback loop.