well, you need to try to get a bird perched up in a tree.., then try to shoot them when you can see an eye, or both eyes.
It's always good to go in an area, (park) where there are always lots of people, the birds there are much more co-operative. Some like the attention, and pose! Pick a bright day, and if its cloudy, wait for the sun to come through..
Also, a key to shooting birds is to try to get the background as far as possible away from the bird, shoot at full 300 mm, and if you have time, move around, and creare a nice colour for the bg. enough tips from me, Eric and the rest of the guys can please add to this.