Patience!! lol
I`m not a big fan of the finger down throat thing,,it winds them up if you ask me.
Patience and gentle handling,, a bit of play as well !! let her nip a bit and she`ll chill out and play.
Spit in your hand and let the ferret lick it as well,,calms them down.
When you pick her up,, be confident,,lift her and have a good hold,,,control the ferret,but don`t hurt her.
Keep at it mate. I have one that works no prob without any hassle,,but when we play she nips HARD! so she gets pinned and slid across the floor!lol she loves it, but the nip is just part of her nature, she`