Keep handling him....ALOT. If you can put him into a show cage similar to what he would be in at a show and practice taking him in and out, opening his wings like a judge would do and keep practicing, he will get better. I have had a modern game breeder show me what she uses as a tool for training, little bits of the soft dog food that comes in pouches, she offers that to them and they look forward to that, its like a reward. Offer something that he likes to take his mind off the fear. You said he shakes, like trembling? Unusual, I always have them bounce off the cage walls and try to get away if they are not sure.
If the bird does not like to be grabbed, grab him and before you put him down again keep a hold, if he tries to get away as soon as his feet feel the floor, pick him up, once he stops, attempt to put him down again. Every time he struggles to get away, when he feels the floor, pick him back up. Soon he will not fear being handled. I have seen many birds that when handled, will just step off the persons hands into the cage. It takes patience, but will make the judge take a second look at your bird over another one who is scared stiff or bouncing off the cage walls.