A skillshot is a type of champion ability that casts a projectile that originates from the casting champion and requires careful aim to hit a target. Circular AoE abilities are not considered skillshots.
There are several types of skillshots that follow the above rules. Depending on the area they affect, they can be Linear or Conic. Depending if they only hit the first target they collide with or if they pass through and damage all units in the area. Also, the latter may travel to damage units in its path, or it could have an instantaneous travel and damage all units in the target area as soon as it finishes casting.
To land a skillshot it is important to consider the speed of the projectile (which is ability-specific) and the enemy movement.
There are also vector skillshots, which are aimed from an area surrounding the champion, as opposed to originating on the champion itself.
This linear missile path indicator is a distinctive feature of nearly all skillshots.
Source: http://leagueoflegends.wikia.com/wiki/Skillshot
Is it possible to create this in Warcraft III?
There are several types of skillshots that follow the above rules. Depending on the area they affect, they can be Linear or Conic. Depending if they only hit the first target they collide with or if they pass through and damage all units in the area. Also, the latter may travel to damage units in its path, or it could have an instantaneous travel and damage all units in the target area as soon as it finishes casting.
To land a skillshot it is important to consider the speed of the projectile (which is ability-specific) and the enemy movement.
There are also vector skillshots, which are aimed from an area surrounding the champion, as opposed to originating on the champion itself.

This linear missile path indicator is a distinctive feature of nearly all skillshots.
Source: http://leagueoflegends.wikia.com/wiki/Skillshot
Is it possible to create this in Warcraft III?