Starcraft 2 – Harassment Guide
One of the basic forms of harassment already tested and proven to be effective, is to gain economical advantage over your opponent. You can do this by eliminating his workers, or interrupting their ability to continue mining. You would then destroy one or more of any buildings or units your opponent has, making sure that whatever you destroy is something that is extremely important for your opponents production. This could be a pylon, depot, or an overlord as an example. What this would do to your opponent is effectively cause problems with his supply chain, and he would need to spend more time and resources regaining whatever he lost through your harassment. Of course all the time your opponent is attempting to resuscitate his supply channels, you are continually building more units and amassing a larger number of soldiers.