Personally, I donate to groups that lobby for better laws for animals (Humane Society, SPCA), one that does rehabilitation of pet birds, breeding and release in the wild (
http://www.tiskita.com/scarlet-macaw-re ... am-update/) as well as groups that protect the environment in general (
http://www.wildernessfoundationglobal.org/ and
http://www.worldwildlife.org/). I no longer donate to places like The World Parrot Trust because they support captive breeding for pet parrots and work with bad places like Loro Parque.
I also do my very best to spread the word and ask people to, please, adopt instead of buying and show them the truth of the conditions of most parrot breeding establishments because not only the large operations (bird mills) are bad, even places where they have a couple of pairs don't give the birds a good life (you cannot love what is producing income for you because, if you did, you would not sell it, right?). People talk about 'good' breeders but how good can you be when you are putting more birds into a completely saturated market and selling to whoever has the money? I ask people to support any new cruelty laws and explain that the information that PIJAC puts out is not only an outright lie but, also, completely self-serving (they basically do not want any rules or laws protecting animals because they are the ones exploiting them and scare people into believing that new laws mean the government will come and take their pets away -as if that was possible!).
Of course, volunteering at a rescue is another great way but I can not do it. I get too involved with the birds, I want to bring them all home and love them and the whole thing ends up been nothing but heartbreak for me as well as a deteriorating health (I tried it and ended up very underweight, sleeping less than 4 hours a day, with my blood pressure completely out of control and such a breakdown of my body that my blood was not even coagulating after surgery and I had to be rushed to the emergency with a hemorrhage after been released).