There are so many things you can do for Earth Day that I can't even begin to stay on top of 'em all, and I worry that half the time, we just wind up looking at all the things we CAN do and wind up feeling guilty about all the things we AREN'T doing. Activism paralysis. The minute you give twenty bucks to the Nature Conservancy you're not giving it to the Audobon Society or Defenders of Wildlife or Bat Conservation International, or using it to buy composted cow manure or a rain barrel or energy-saving lightbulbs.
I mean, I'm into native plants and gardening for wildlife, and that's great, that helps--I have to believe that helps--but I'm not setting up solar panels on the roof or recycling tires or planting trees in Africa or lobbying for fair trade coffee or washing ducks or picketing polluters or biking to work or driving a hybrid...
Well, you keep on like this, and pretty soon you're convinced that you're one of history's greatest monsters (apathy edition) because of all the things you're NOT doing.
Hell, even wildlife gardening becomes a huge issue if you look far enough, because, as with so much in life, everything bleeds into everything else and pretty soon you realize that controlling soil erosion requires more sustainable farming which requires a better standard of living in developing countries and you get your biggest bang for the buck on that by educating rural women and providing them with birth control, and pretty soon you're trying to save tigers by handing out condoms because the world is just that insanely complicated.
I think the important thing is to pick something you can do. One thing you can focus on. For me--wildlife gardening. This is my thing. This is where I make my stand. Obsessed? Oh, sure, maybe. I'll buy fair trade coffee and foster strays and use energy saving bulbs, too--but gardening for wildlife is the way that I can stand up and say "The world is better because I made this little patch of dirt into something special." It's the thing I can get my head around, the thing that I can sort of see the edges of, the thing that I can do that I know makes a difference.
Yours might be different. My dad got into solar power and bio-diesel. Kevin traps and spays feral cats. There's a zillion issues out there--water conservation and wildlife rescue and wind power and anything else you want to name. Find the one that matters to you. Like to cook? The local food market and farmer's markets are a huge and oft-overlooked issue. (I was just at one!) Want to restore a prairie? There are organizations (at least in the plains states, where, y'know, you've got prairies to restore.) Install a rain barrel, buy local food, make a compost heap, plant a tree--whatever. You have options. And you don't need to do everything.
Just do one thing.
Find the one that speaks to you. Find the one that you want to read about and go out and shake people by the shoulders and yell "Oh my god, did you know how much blank we blank in this country every YEAR?" (If you have no such issue, I am sure that commenters would be happy to provide one.)
So for Earth Day--and the rest of the year--I urge you not to get overwhelmed. Pick the thing that matters to you, the thing that makes you crazy or makes you happy or makes you furious--whatever it takes--and make your stand.