You'll get there- We all started with baby-steps- snakes do too, especially as pets in our confusing world. Just encourage their natural instincts, & any time you offer prey, it's best at night, in dim/dark room, & be as much a part of the background as you can.
When using tongs, be subtle. And never make it seem like the prey is approaching the snake- that's not natural at all- rodents don't run up to snakes & volunteer to be dinner. You want to make it appear to cluelessly pass by, near but just out of reach of where the snake is hiding, to elicit the snake to follow & grab. Jiggle the prey only slightly- no break-dancing-