I agree with mele, no shoulder, and be confident and stern. My little green cheek was quite the piranha when we first got him. And he only became worse when he learned that if he bit, id draw back and leave him alone. It got to the point where simply opening his beak and extending his neck forward was enough to get me to draw back.
I finally got sick of being dominated by this tiny little feather ball and started to push past the bites. If he tried to get me to draw back, i'd be even more persistent. You have to be really stern with them, show them whos boss (don't ever hurt them ofc). Just let them know that when you want something, it's gonna happen wether they like it or not, no matter how long it takes. Don't give up unless your bird is getting visibly stressed out and upset, you don't want negative experiences surrounding you.
That's what worked for me anyway. I also read that direct eye contact is important when putting up with a fiesty bird.
You could also just shower him with treats to keep his beak busy and make your arm and hands really positive. There's alot of ways to discourage bad behavior.