It's all in the cutting...You're not making little scallion mums. Don't soak.
Slice the top tip of onions off, but don't touch the root end other than really groady stuff.
Peel off outer skin. Put it on a board upright and cut 1/4 inch "slices" like you'd cut a pie (1/4" on the outside peel. It will be smaller towards the center) to about a half inch to the root end. Be gentle and use a thin sharp knife for this. You don't want to snap the onion strips.
Kind of fluff the onion by hand. I equate the motion with the way you'd shuffle a deck of cards with your thumbs only more gently.
Then that's it. Dust it making sure you get it in between all the little strips. Batter it, let it drain, and fry away...
They do make a machine to cut them but I can't see paying almost a G for something like that.
Bottom line is it's like getting to Carnagie Hall. Practice Practice Practice.