I don't have a guide to making people into feminists, but here is a bit of my history. Maybe I'll work backwards in time...it's difficult to say how influential all the distant past events were. And, of course, my memory isn't as clear as it once was.
I asked for good writings about sexism
In August 2011, there was something about sexist jokes that I was able to ask someone I knew about. Her answer was, basically, something like "anything is fine if the women around you are fine with it". I wasn't totally satisfied with this, and I went to Yahoo Answers to ask some more. You can see the question I asked here [still archived on wayback machine], such as it is. The answer directed me to a tumblr ("stfusexists", which has since been deactivated), which I thought was great and was very happy to have found. In turn, it linked to much more online material to check out (such as Feministe, and many other tumblrs). I really got into it.
I went and read about feminism on my own
Late 2010, I had a vague notion that feminism was something good (I think I was also aware that my older family members were of the opposite opinion), and I wanted to know more, so I went to Wikipedia etc.
I don't remember much here, but I can't forget that on one of the wikipedia pages I saw mentioned that there was a book called "The Ethical Slut". I had a strong negative reaction just to the title of this book (having been brought up in a very sex-phobic home), I could hardly believe it. And I decided to read it, just to see how someone could be so "wrong", or something.
That's not how it went though. As I read it, I found that I actually could not disagree with them, and that actually a lot of the things they said were things I myself had also thought about, and agreed with. What I discovered is that I was holding two different contradictory belief systems in my head. I just hadn't noticed or confronted just how self contradictory I was.
Now I more firmly had a better (and coherent) system of morality, and this probably changed my life profoundly. I also became an atheist before the semester was done, partly due to this new understanding of how relationships should work, even relationships with a god (I'll need to make a page about that part of my history too).
A high school LA teacher
She showed us stuff about objectification in advertising.
My classmates could get some credit for influencing me too, many of them were pretty good.
My high school thoughts similar to "privilege"
I thought about how, since people's lives are so different, they might come to see different things as "normal". Stuff like that.
I was mostly thinking about different social experiences. People with a rich social life compared to those (like me) without.
For example, how attractiveness would change things. People want to look good in front of attractive people. Therefore, I suspected, what attractive people see and experience is not the full story (it could be like a perspective sidewalk drawing, or a virtual reality simulation). People want to be liked by attractive people, and try to get relationships with them. Therefore, their knowledge of how social interaction (and social life) works could be different (and I'm pretty sure I knew that they probably had to deal with some annoyances because of this that I didn't, too).
Leaving aside "attractiveness", most of my peers seemed to have rich social lives, well connected with many people. This was so different from my own life that I guessed there would be a large gap in mutual understanding.
When I heard of the concept of "privilege", "the invisible backpack", etc, I was like "ah, yes, I get this".
Some of my feminist thoughts before 18
When I was like 13, it really struck me that men seem to be the ones who write all these movies. I don't remember everything I thought, but I might have glimpsed the idea of an epistemological bubble created by media made mostly by men.
Religion
Our religion was not very feminist, to say the least.
Parents break up
In late 1997. And apparently my mom took us away because my dad made a threat (which I never found overly surprizing, he did have an unpleasant temper). Obviously this didn't turn my older brother into a feminist though. But viewing my father as a not very great guy could have combined with my own values (different from those of my older brother, who was another unpleasant guy in my life) to have some result?