The UK's concept of "Presence Patrolling" is ensure that the bad guys cannot do stuff, because you are not there to stop them. "Suppress the enemies freedom of action" - just like any patrolling!!

In Northern Ireland, it actually meant lying up in abandoned houses, or woods, sometimes for a couple of days, then suddenly moving into an area unexpectedly.
The object was to appear unexpectedly from an unexpected direction.

In more benign environments it's just showing the flag, and sending he message "don't f**k with us or else," combined with "You're safe because we're here."

All blinding common sense really.