To trim the hedge well, it’s necessary to cut with precision.
Wiktionary has a different take on this idiom.
hacer la tijera
(idiomatic, sex) alternative form of hacer la tijereta (“to scissor”)
(idiomatic) to jackknife (to accidentally turn the cab of an articulated truck)
Hmm. Unless you find yourself in a very specific scenario, where it is very clear that you are doing something else (eg, you are playing charades and representing kitchen utensils, or something), I’d say that the sexual meaning would be the first thing that would pop in mind : D
Additionally, I think we’d usually use them in plural “las tjeras”. And since we are talking about bushes (the green ones ; ) ), “las tijeras de podar”.
So maybe, “[…] manejar las tijeras (de podar) con precisión”. Or simply, “usar las tijeras (de podar) con precisión”