Unfortunately, there are still businesses out there that look at clients and prospects simply as pounds in the bank. (Although I'd like to think that this didn't include you, as you have the good sense to be reading this and looking to better yourself!)
Ask great open questions to encourage your prospect to talk to you. Be genuinely interested in the response. Practice active listening—nodding, encouraging, smiling.
You don't have to be super-intelligent to be a good conversationalist; you just need to know how to ask good open questions. People love to talk about themselves, even shy people, given the right questioning.