- At the simplest, just talk to other people about your feminist ethics. This lets them know that normal people like their friends, neighbours, workmates and relatives can be feminists and still be friendly and sane.
- Volunteer some time to an organisation which helps women. There is a wide variety of organisations, some overtly feminist and others not, but any action you do which helps other women is an act of feminist solidarity.
Then it gets a bit tougher.
- Object to any speech or action which demeans, constrains and/or harms women, whether you know the women concerned personally or not.
- Do not accept that there is a “war between the sexes” and challenge anyone who assumes that there is and that it is natural.
- Do not accept that “men just can’t help being X” wherever X is something that women are complaining about as demeaning or harmful to women (or gender roles that are constraining, demeaning and harmful to men).
If you are a pro-feminist man, this is especially important, because when you don’t object:
You are missing an opportunity to help stop the bad guys.
You’re missing an opportunity to stop the real misogynists, the fucking sickos, the ones who really, truly hate women just for being women. The ones whose ranks you do not belong to and never would. The ones who might hurt women you love in the future, or might have already.
‘Cause the thing is, you and the guys you hang out with may not really mean anything by it when you talk about crazy bitches and dumb sluts and heh-heh-I’d-hit-that and you just can’t reason with them and you can’t live with ‘em can’t shoot ‘em and she’s obviously only dressed like that because she wants to get laid and if they can’t stand the heat they should get out of the kitchen and if they can’t play by the rules they don’t belong here and if they can’t take a little teasing they should quit and heh heh they’re only good for fucking and cleaning and they’re not fit to be leaders and they’re too emotional to run a business and they just want to get their hands on our money and if they’d just stop overreacting and telling themselves they’re victims they’d realize they actually have all the power in this society and white men aren’t even allowed to do anything anymore and and and…
I get that you don’t really mean that shit. I get that you’re just talking out your ass.
But please listen, and please trust me on this one: you have probably, at some point in your life, engaged in that kind of talk with a man who really, truly hates women–to the extent of having beaten and/or raped at least one. And you probably didn’t know which one he was.
And that guy? Thought you were on his side.
As long as we live in a culture where the good guys sometimes sound just like the misogynists, the misogynists are never going to get the message that they are not normal and that most people–strong, successful men included–do not hate women.
from Kate Harding: On being a no-name blogger using her real name
What else can we do for feminism?
Finally, A Feminism 101 Blog 
This link might make a nice follow-up to this post:
Stuff What Boys Can Do
Harriet Jacobs is collecting stories of feminist-leaning interventions and actions by men, to inspire and edify. If you’re reading this, male, and curious, here are some ideas for you in answer to this post’s question.
Great summary. I’d like to I’d also like to add:
Don’t allow comments about the “way all women are” slide. My brother for years would talk about how “women are terrible at” this and “I hate when women” that. Finally I began correcting him with “people are terrible at” and “I hate when people”. I don’t know why it took so long, but he eventually realized he was attributing the actions of men to individuals and the actions of women to a group.
Those comments are easy to miss because they aren’t immediately aggressive, but I think reminding people regularly that people are people can go a long way toward equality.