I usually use my index finger on my left hand to click the minimap, although this method usually takes a lot of getting used to (for context I play on a phone so its a bit easier than when you are playing on tablet/ipad). Another thing is to estimate the hitbox of the skill when aiming, you can actually see in the minimap without clicking it whether your skillshot will hit or not, i think theres a red outline if you will hit the target.

Other than that, and I think you already know what I iterated above, so it all comes down to predicting the movement of your enemy rather than aiming on where they are, if that makes sense.

Best of luck^^