Genuine common interest is always a breeding ground for good conversation. It is not recommended that you try to feign knowledge in a certain topic simply because a guy likes it. He will quickly notice the fraudulence and credit these actions to be the signs of a disingenuous individual.
If you are first meeting a guy and are unaware of his interests, you can always discuss sex…intelligently. Every man, especially if he is dating, has a high interest in your physical interests. This is not being said that the discussion has to be vulgar, but sexual activity can be the anchor point of the discussion. You can bring up a story about two co-workers having sex in the office, celebrities and their sex tapes or the gratuity of sex in music. The conversation does not have to be personal by any means. ( A mature man will not blatantly attempt to dive into conversation about your personal sexual interests. )
Based on conversations with several women, most, think that talking about sex paints them in a promiscuous light. This is a myth. In most cases, discussing sex will quickly break the ice and the conversation will flow, often segueing into other discussion topics. By taking this route, a man will feel as if you are someone whom he can talk to. This is a positive quality that men appreciate in women. This works in their factor when we are making the choice to enter into a relationship or not.
Just a little insight. I hope this helps.