What does it take to be an ally?

One of my friends and I were having a discussion the other day about the LGBTQ groups at our school and whether or not specific types of people can consider themselves allies. As a queer woman, my perspective has always been that being an ally means that you treat the people you're allied with decently, which in my view means that you are respectful of them and their struggles, you don't actively do things which contribute to their marginalization (Which does not mean you never do such things, but that you do your best not to and, ideally, acknowledge that you've benefited from systems that marginalize others), and you stick up for them when you see others doing things which marginalize them. For example, you say "I'm not okay with that. Making that kind of joke isn't funny, it's wrong" if someone makes a joke about trans* people. In general, I don't expect people to become activists beyond taking the struggles of a marginalized community into account when they vote.

This, ultimately, is the difference between my friend's perspective and mine. In her view, an ally must be a serious political activist, someone who spends significant amounts of time devoted to organizing for and advancing the cause, whatever that cause may be. I instinctively balk, though, at agreeing with this, because after all, I'm not that much of an LGBTQ-rights activist. As a sexual minority, it seems a bit gauche to expect my allies to do more to advance my cause than I do. I can't think of any particular philosophical reason to accept one set of minimum qualifications for allyhood over another, though.

What does everyone here think?

EDITED TO NOTE: I don't want to say that members of any particular group should give anyone some sort of Badge of Allyship(TM) if they don't consider that person to be a good ally. I know that I have a lot of privilege myself, and I'd never ask anyone to call me an ally of their group if they didn't think I made the cut. I'd ask how I could better support them, but that's all. Just wanted to add the extra clarification.