If you don't supply it, the opponent will. Whatever the goal, it must be seen as part of the overall campaign. It is not an end in itself and must not take away support from other aspects of the campaign. Militant action is always a trade-off. It will alienate some while drawing support from others.
Discretion is needed to weigh up the usefulness of a particular action.
The time after an action can be an anti-climax. Plan for this in advance - keep your goals clear and work towards them by keeping the preceding stages going. Plan how to deal with temporary setbacks or victories. Also look after the activists. This can be difficult if key people have maintained the organisation over time but is vital to keep them sane and attract new people identifying small victories along the way to the greater goal.