Steve posted an article or a podcast a while ago about Erin's beliefs about people - that we're all connected in the end, and that we already know everyone. I had a go at installing this belief and have found it's greatly improved my abilities with this stuff (I had exactly the same problem until recently).
Also reminds me of a quote from the podcast 'uncomfortable questions' (which is great and located here:
'Uncomfortable Questions' it's a podcast interview show with interviews of ordinary people about the deep questions in life, like the existence of god, what does love mean, etc.). An interviewee once said that he thinks of everyone as being separate islands - on teh surface they're divided by water, but if you go deep enough below the surface, they're all connected to one another.
And I second the suggestion to read Carnegie. It's a fantastic book that needs to be read and re-read. Also, Larry King's written a book called 'How to talk to any body, any time', which I haven't actually got into yet, but I've heard it's good (plus, y'know, Larry King...)