I tend to think that if I talk about something I'm interested in, other people will be interested in it too. No matter how fascinating the underlying concept to me, nor how well I think I'm explaining it, this almost never happens.

Heh, I hear you on this one.

My initial response was to try to "fit in better" by simply avoiding those topics and sticking to smalltalk. Worked really well for the purpose, but also made me feel stupid - and worse, it drastically reduced the number of interesting people I got to know. Essentially, while most people found the stuff I care about horribly boring, occasionally I would run into someone to have a worthwhile chat with; but if you eliminate all the possibilities for such chats, they never happen.

So I resorted to introductory stories: interesting anecdotes and personal tales that have something to do with the subjects I'm interested in, even if they are tangential to the main area. If you draw people into the subject first, they are much more likely to allow you to expound on the boring bits as well.

For example, a side interest of mine are factors that change people's motivation patterns. Essentially impossible to talk about directly. But I can introduce the subject in two steps. First I start smalltalk about the financial crisis and the motivations of bankers responsible for it. Then I segue into short descriptions of some of Dan Ariely's experiments (where he showed that amount of theft increases proportionally with the number of steps a person is removed from actual, physical money), which can be described in a way that most people find very intriguing. THEN you can go into more technical details, and have a spellbound audience.

All of the above is probably a very obvious approach, but was quite a revelation to me. We all have our little blind spots...