Let's Talk(Big and Small)

I start with small talk when talking with people I don't know. Big talk sort of just happens naturally if I click with someone. I suppose an example would be when I was at a 4th of July party tonight. I was playing pokemon TCG and got into an intense discussion about pokemon decks and strategies. If I meet someone and we just don't seem to have anything in common I don't really know how to go beyond small talk.