Ability to continuously demonstrate government weakness, erode government influence, and cause government to alienate itself from people.
Support of people (both psychological and physical) for intelligence, recruits, shelter, transportation, refuge, food, money, and medical aid.
Access to (more or less permanent) safe sanctuaries or base areas and/or fluid bases that can be shifted from place to place, away from enemy forces—in order to rest, recuperate, repair materiel, etc., as well as indoctrinate, train, and equip recruits.
Use of stealth/fast-tempo/fluidity-of-action coupled with cohesion of guerrilla bands as basis for:
dispersion, to arouse people, to avoid adversary strength, and to force government to thin out, or disperse, its strength;
concentration, to hit and wipe out isolated fractions;
shifting of effort (in these as well as other activities), in order to gain and keep initiative.