Very interesting topic and I’m surprised someone from Psychology hasn’t chimed in on this yet!
While I’m not in as much of a technical field as many others here, I’ve encountered this challenge before with the language I use to explain aspects of my field that people know about but just don’t know what it was called in technical language. And I learned recently that sometimes research psychologists are thought of as weird by the community when trying to recruit participants (learned from a POI on interviews) as well as talking to others about that no in fact I don't/won't psychoanalyze you or your child (such a common question, no we are not all clinical!). Haven't gotten the smart comments as I'm an undergrad and not sure if I will...
I openly admit I don’t have to worry as much about finding a common topic of discussion as I get a lot of kid stories (or explanations about why they don’t like kids) when I mention what I study. (So yes asking Stay at Home moms about their kids is a very good way to get them talking...) Though I do agree that there is some very good advice about finding another common topic already (such as from Page228)!
I agree with GeoDude! on explaing your work. I’m not a grad student yet (undergrad – waiting on my last chance of admission this year) but have worked with specialists (my PI and lab mates) and nonspecialists (parents from many different backgrounds) since I’ve started doing research. At first it was actually much harder for me to talk to parents about what I was doing as I had a little blurb on what we were doing in nonspecialist terms that we used to recruit but I couldn’t figure out what to say when a parent asked something else. When I had my own study and more technical knowledge, I found it easier to further explain what I was doing even to a nontechnical audience (and have to children, parents, and other undergrads). I think my increase in knowledge allowed me to begin to think about my work in different ways and at least for now feel like I’ve arrived upon a way to explain my current work to specialists and nonspecialists.
And I like the advice about trying to find some practical implication of whatever you are studying that makes it interesting to others (some application to a well known disease, interesting application of a theorem, etc). I'm currently writing an interdisciplinary lit review thesis (my second UG one) and once got the advice of making sure to try and be able to answer “why should I care?” when this “I” is someone from various backgrounds (another academic in your field, another academic in a closely related field, someone who knows nothing about your topic, etc).
I think the best advice for learning how to explain your work to others is just to practice doing so!
Oh and my dad is a prof in a very technical field that is not well known to nonspecialists so sometimes when I'm asked about it I just have to explain very generally what the field is, what technique he uses in his work, and a very broad application of his work and they are satisfied.
(Long thesis writing procrastination post over)