"The only bite that can't be rewarded is the one that never occurs" - Barbara Heidenreich
@Alyssa M. - the best way to start step up training is to teach the bird to look at your hand. Reward that behavior. Then reward the bird for moving towards your hand. Then reward for touching your hand. Reward again for stepping up!
Birds in new environments are often scared and will not act how they would normally act.... so it may often appear as if a bird is well behaved when you first get them and then they revert. May be part of a survival instinct to be cautious about their environment before feeling comfortable enough to communicate with you. It's because of our lack of understanding about our birds that results in us getting bit, though!
BTW, I recommend avoiding "The Parrot Wizard" and "Bird Tricks" at all cost! There are some *great* trainers out there who have gone above and beyond to learn the science of behavior and work with animals in a force-free manner that doesn't put the animals, nor themselves, at risk! This includes Barbara Heidenreich, Lara Joseph, Susan Friedman, Hillary Hankey and many others!
@Jessie1285 - As I mentioned to Alyssa, bites are often because of our lack of understanding. Communication is a two way street, however when it comes to birds, it's typically a one way street... i.e. we expect the birds to do as we please and without consequences. The birds bite to say "I'm afraid", "I'm not comfortable", "Not right now", "I don't understand what you want", etc. They're trying to communicate with us and tell us to back up or slow down, but when we refuse to "listen" to these signals (eye pinning, beak open, wide stance, neck feathers ruffled, raised wings with spread tail and fluffed up body, etc) we get bit.
If you want better results then slow down! Take several steps back! Try to avoid getting bitten by learning to read your bird's body language and backing off before the bite. Then, try to figure out a different strategy to get the behavior that you want. Maybe give the bird a few minutes alone before requesting the behavior again. Work WITH the bird, not against them.
@Laurah - same advice as the other two!