One that I've been told to do is to put your Show bird in a cage and a couple a times a day take him/her out. Get them use to being handled.
You can train them to pose in a cage with treats. Get other people to reward the bird for posing. They call it cage training.
Don't wash your birds with soap, just rinse them off about 7 to 10 days before the show. Then after being rinsed off from dirt spray mist in solution Glycerin with water. Glycerin is a vegatable base oil that they will preen them selves with to get the high sheen.
There are other more trait detailed things you can do to get the bird looking great. Great topic for ALL of to read and I thank you for posting it!