How do troll people with your archers?

Right click on the unit
As fast as you can, right click the ground
Wait for archer to reload
Repeat

Clicking the unit can sometimes be replaced with "H", but only if you don't care what you hit.

Right click on the ground behind the unit you want to kill, right click on the unit you want to kill then wait for the archer to reload.
Keep right clicking the ground behind the unit while your archer is reloading or in other words, keep moving forward. Right click the unit to shoot, keep repeating this.
Like saintdane said, right click can be replaced with "H", you can also use "S", which is easier since you don't have to move your fingers that much.

This thread's answer has already been answered by the thread you made last week. As such, this thread is redundant and shall be closed.