Just play him a bit, try practice range, and learn the head hit boxes and you'll get the falloff eventually. I'm getting better and it took me only a few hours of hanzo. I'm trash at scatter arrow but I can do the rest lol
Notice how hanzos stock reticle has 3 dots? Those are range modifiers if you didnt know.. the lowest dot is for long range and as you scale up the reticle the closer they should be to you