slingshot bow and arrow, how to improve shot accuracy

I am a superfan of slingshots, and in my opinion,
slingshots and darts instead of arrow are one of the greatest combinations. I typically put slingshots in the same category as a fishing pole. I’m pretty sure I remember slingshots being standard equipment for me and the boys in my neighborhood as a child. The 'arrow' I used with a slingshot was in fact a big nail with some fabric strings at the end. The strings were for directional control when arrow flied in the air. It's a simple and crude slingshot arrow, but sort of functional. I got many basses with it. Now I use the professinal darts like below, the accuracy is much better than shooting a real arrow.

5 pieces 'fierce flying shark' slingshot fishing darts