[inkista]

Here's what I've learned, chasing raptors in my local canyons:

1. They deliberately fly so that they'll be backlit. It's nothing personal (although it sure feels personal), but they want to have the sun at their backs so they can see prey. Pay attention to the direction of the light.
2. Birds in flight: keep both eyes open. It'll help you track and get the bird in frame that much faster.
3. Go for the best, longest lens you can afford. You can never get close enough for birding.
4. Teleconverters are nice, but sometimes they're not worth the autofocus hassle. Do research before buying one--do not assume all lenses will work with them or have full functionality. Learn about taping pins.
5. Know about camera shake vs. focal length, and the shutter speeds you'll need and how to get them.
6. Learn your autofocus system's quirks. Single-point, servo vs. non-servo mode, using the focus-limiting switch on your lens, etc.
7. Always have your camera out and ready to shoot BEFORE you start hiking to your birding spot. I can't tell you the number of red-tailed hawk shots I've missed to teach me this lesson. The readiness is all, when you've got half a second to get a shot.
8. Good handholding technique and monopods are things you want.
9. A car makes a good blind.
10. Learn to post-process. You will crop. You will sharpen.
11. If you don't have one, and you live in North America, get a copy of The Sibley Guide to Birds. It makes everything a lot more fun.