This is an interesting topic because I remember being on the other side of the fence! A few years ago, before I got into lucid dreaming, one of my friends said to me “earlier on I had a nap and I think I know what happens when you fall asleep!” He then described what sounded like hypnogogic imagery (flashing lights and patterns, weird sensations)
My response?
“What?! Shut up mate, when you fall asleep you just fall asleep, simple as that! What are you talking about?”
At which point he dropped it.
Ironically years later I got into lucid dreaming and talked to him so much about it that he had a couple.
Anyway, I’m sure everyone here can associate with, when telling someone about lucid dreaming, THAT look on their face… THAT kinda freaked out, “okaaaay”, slightly patronising “i’d better keep this crazy guy talking” face. lol
Well, don’t let the face put you off. You’ll soon have them interested if you go for the right approach…
- first of all a brief description, emphasising how it is different from a regular dream “you feel like YOU are actually there in the dream, thinking clearly and logically as you are now”. then prepare for comments…
“I’ve done that!”
Ask them what they chose to do with it. If they say flying or sex they are most probably naturals. Express your envy. 
If they describe something that sounds like a normal dream, try to restate that definition again in a different way.
“Hmm… I’m not sure if thats an actual dream you are talking about there” (you get this from psychology students a lot, sadly!)
Simply state that Dr Stephen LaBerge of the Psychology department at STANFORD UNIVERSITY has published a lot of research in the field and is an expert (DON’T mention the induction devices yet… leaving yourself open for a “sounds like a con trick to me…” argument)
“why would you want to do that?”
Easy enough to answer… “access to your own personal utopia”, “laws of physics and reality no longer apply” “you can interpret your dreams WHILE you are dreaming them to get a better understanding”, “rehersal for real life” etc etc etc!
If they dont ask how to do it give up. lol If they do I start with reality check technique because it really is an intriguing concept. Then nap technique because it is the no.1 technique. I like to mention alchohol can assist it too as that can be quite popular…
Then describe the best bits of your BEST lucid dreams. Mention that Tibetan monks have been doing it for thousands of years. etc etc
If they still arent interested… demand they tell you why!!! lol