Holding the OTT slingshot sideways and the pouch anchored on the cheekbone, I aim via the top edge of the fork tip, which runs parallel to the upper side edge of the upper placed flat band. This yields consistent accuracy (see the attached image). Knowing which eye is dominant when aiming is crucial too. Holding your breath just before releasing the pouch increases stability.
So-called "instinctive shooting", without a steady contact anchor point on the side of the ear or on the cheekbone, is in any case much harder to master: significant practice is required for this technique - which does, however, come with the benefit of higher power linked to more "acceleration" time of the bands (or tubes).
A notch, or other reference marks (e-g. colored sticky tape, a dab of paint) at this position of the fork tip of slingshots without sights ensure a steady aiming reference too, but it always needs to be as close as possible to the upper edge of the bands.
The 10 yard fiber optic dot on the sights commonly seen on Chinese slingshots lies maybe 1 mm above the upper side edge of the flat bands: this very slight gap clearly impacts shot placement on the vertical level, as that initial gap increases over a given distance and affects the POI.
It needs to be compensated for by aiming very slightly above the target, also bearing in mind that the trajectory of the ammo is in any case never perfectly linear i.e. the POI drops off depending on ammo weight, initial thrust, and the distance involved.
It is for this reason that hunting bows have sights with fiber optic sight positions for various distances.
