A good conversationalist strikes a perfect balance between talking and listening. They pick up threads to create a multi-layered conversation and a sense of intimacy; the other person feels reassured that they are listening and interested.
It is important to set the conversation off well. Try to think of an alternative to the usual 'how are you' or 'what do you do?'. Gentle humour, shared observation, flattery and the occasional well-placed compliment all oil the wheels of conversation.
Ask questions, but don't conduct an aggressive interview - there is a fine line between interest and intrusion. Familiarity comes with time, so be aware of unspoken barriers. Avoid strong opinion or stark honesty; an occasional frisson is interesting, but controversial views may offend, and amongst comparative strangers there is always the risk of a tactless blunder.
Never talk about money, illness or death. Bluffers and serial liars always get their comeuppance; name-droppers and braggers bore everyone.