How we change what others think, feel, believe and do
Make regular, random, small attacks on the enemy's positions.
Get in quickly or sneak in quietly, do some damage, then get out again quickly, before they can respond.
Make these attacks in a way that they are unable to predict what you will do next or where you will attack.
'Shoot and scoot' is a name sometimes used to indicate the idea of getting in, shooting, and then scooting away before they can catch you.
Harassment is not intended to gain position. It's primary purpose is to keep the enemy on its toes, unable to relax and always worrying about where the next attack will come.
When the attacks are random, the enemy has to keep troops on alert in all quarters. This reduces their ability to concentrate an attack on you and prevents the troops from resting and hence being emotionally ready for attack.
Harassment thus wears the enemy down with relatively little effort. For your troops it can be relatively safe fun as they are not being asked to engage in direct combat and not over any extended period. Of course there is danger, but often this is just enough to make it exciting for them and let them come back telling tales of the enemy in disarray.
In the wars in Afghanistan both against the Russians and against Western forces at the start of the 21st century, the local militia would attack supply columns and encampments on an unpredictable basis. The Western forces also used the same methods in return.
In an argument, make unpredictable attacks on minor elements of the opponent's case. When they defend, back off, but then attack somewhere else a short while later.