One thing that's worked for me, whether with snakes, ferrets, dogs, cats, etc....
I find it important to try to think like the animal. Think about their natural environment, how they hunt, what approach do their predators take, etc....
And then think about how your presence may make the animal feel, what fears the animal may have.
With feeding, place yourself in their situation. How do they hunt? How do they approach prey?
You can the apply that info to your feeding technique, handling technique, etc...
And the world as a whole seems to be shying away from common sense and common courtesy (not implying this is true of you, just a general statement).... remember common sense is your friend.
Good luck!