Your suggestion to nerdfiles of Toastmasters for practice is great, I hadn't heard of it.

A book I really liked, which I hope has helped me with social interactions is Dale Carnegie's How to Win Friends and Influence People:

http://en.wikipedia.org/wiki/How_to_Win_Friends_and_Influenc...

I also agree with your point that mentioning Github to a client (probably a non-developer - that's why he's hiring you :) ) was a bad idea.