Priming the cells with a small drop of royal jelly or even diluted honey makes it easier to float the larva off the tool. Don't flip over the larva. An unsteady hand is helped by bracing it lightly on the comb. Good light is essential, a headlamp works well, sunlight is ok if done quickly. Magnifying lamps are useful for those with poor eyesight.
Some people are expert grafters from the start, others take more practice.
Grafting is what prevents most people from attempting queen rearing. This is unfortunate, with an hour or two of practice, anyone can acquire this valuable skill. Give it a try. The Breeder hive Graft from your best colony, or purchase a selectively bred breeder . By placing an empty brood comb in the broodnest 4 days before you graft, the larva will be the right age.