Is it possible to learn how to be good at banter and small talk?

Dahh, a dumb English guy here! I thought it came natural to the female gender.
The best bet though, is to listen to what is being discussed, and only add to it if you know something worth talking about. Otherwise, listen and remember, it will come in useful later.

Good luck pretty blonde.

Study what people are talking about, listen to them, pick up the general vibe. Then replicate. Much of it is just filling silence with mindless shit. You ask about their weekend even though you don't really care. You talk about the football last night that you didn't watch. You comment on something in the news. It's that kind of crap. The sort of stuff you'd say to someone at the bus stop to make it less awkward when they try to engage you in conversation.