Whenever people at the gym ask me for delt help, I always make them grab the 10lb dumbells, sit in a chair, and do lateral raises that break parallel. Tempo is 3 count up, brief pause, 3 count down.
I've rarely had anyone make it to 20 reps without having to drop the weight because their delts are on fire.
IMO there's no magic movement. Just learning to control the weight with maximal contraction and tension, while going slow enough to feel the movement and minimize any swing.