A question I get, as a male feminist, is how I came to feminism. While it might seem a bit personal, and hard to extrapolate to a wider audience, I think my personal experience is very illustrative of something that all feminists need to do.
Although I didn't identify as a feminist probably until I was in high school or college, I always held the fundamental political beliefs of feminism. That is, I believed in equal wages, was in favor of laws banning forms of discrimination, and supported women politicians. I was a rather typical "liberal" and "nice guy" in that I believed in a great many abstract policy objectives, but I didn't incorporate any of those beliefs into my daily life.
As I moved to college, a bunch of my friends entered a men's feminist group and I sort of tagged along, though enthusiastically, and I learned a lot more about feminism. I starting reading a lot of feminist blogs, starting buying a few of the less academic-y books out there and reading those too.
But I still made sexist jokes among friends, I was still very much a "nice guy" (or so I think, in retrospect), and even though I had abstractly accepted feminism, I had not incorporated it into my personal life. I didn't view my world as a feminist, and I didn't treat my friends, women and men, as a feminist would.
One day, a friend of mine, a girl, who was then and still is one of my best friends, and I were hanging out. I couldn't tell you where or what we were doing, but I think we were perhaps on our way back from a party, or maybe going to one. She mentioned to me, very casually, "You know, Jeff, sometimes you make these sexist jokes, and they're hurtful."
It was in a very casual situation, and perhaps my remembrance of it gives it more weight than it really had, but that was my "click" moment. Somehow, that casual comment, even though I'd already read about and believed all these things about feminism, hammered home the fact that I was not living by the principles I purported to stand by. How I was living was hurting my friends, and not unlike other young people, my friends meant everything to me.
I've described it in a few other posts, but like a recovering alcoholic (chauvinist), I realized how my personal life was structured around the same societal forces I had read about. I won't pretend to now, and I certainly hadn't then, figured them all out, or struggled to remove them all, but I tried. And that was my "click" moment.
So there's a bit of a lesson here, even if only anecdotally. Speak up. If you have someone who says they're a liberal, a progressive, or even a feminist, and you see them engaged in a pattern (or even one instance) of sexist behavior or speech, call them out on it, but also tell them how it affects you. How you, their friend, someone in their life, is hurt by it.
That's something we all have to do, but especially male feminists. I say especially, because, unfortunately, a lot of guys will shrug off the protestations of their women friends when they call them out on sexism. While I didn't, in my anecdotal case, I know a lot of men who do, and I know that the pre-feminist me probably would have too.