Being a social butterfly is very simple. I used to be one. (Beleive me, it can be very unproductive and totally useless, as watching TV).
Many good advice is already given. My key answer is - don't overcomplicate things. Simplify!
It's all about capturing/releasing attention. If there is silence, uncomfortable for you, it means, it's your turn to capture attention. Play your character, as you were on theatre stage. It's your part of the play now. Do at least something. Anything.
With some practice, you'll get annoying
Now some particular details. You usually do all this, by asking questions. And if the person stays silent, it means you're asking wrong questions. Or (it happens more often) the person just doesn't want to talk to you by some inner reasons, and all you can do is to find another person to talk to.