I've shot humming birds before, and all it takes is a little searching and waiting. Look around for a while until you find one, generally hummingbirds will return to that section of flowers, once you've found one set up your camera on a tripod, take a few test shots to make sure you have your settings down and ready. Make sure you're set up a good 10 ft away, grab a chair and wait, once it returns you should already have you're camera aimed and focused so just CLICK and your done!