I'd convince someone like me by talking about privacy, which was my first
motivation. But more and more, it became the fun and powerful programs, and
the possibility to do what I wanted with them.
First problem : I'm not properly informed about privacy. My arguments and
knowledge are incomplete, and I can barely convince myself when I hear myself
talk about privacy to someone else. It's a complex subject, and I doubt it's
a good idea to stay with approximations, no matter how valid they are. It's
very easy to sound paranoied.
Second problem : The "out of the box" experience is still way better than
anything proprietary, but there's still some serious work to be done. This is
a good example:
https://trisquel.info/en/forum/maintaining-security-and-avoiding-surveillance
A dual boot is risky, a virtual installation is more manageable, but very
complex for most people.
Even an installation isn't a straightforward task (making a Live USB for
example).
The fact is, it takes work. Being the "hacker friend" can help.
I also really like root_vegetable's idea of having GPG links in the mail
signature.
So in a nutshell, IMO:
- REALLY know what you're talking about, and articulate it efficiently and
effectively.
- create interest (mail signature, talking briefly about privacy, or a cool
program), but don't push it, don't force it, let it happen naturally (crap,
I'm pretty sure those lyrics are copyrighted).
- Make the transition as smooth as possible for non-tech people : help by
giving time for example. Lend a Live USB, or make a bunch of Live CDs.
