The main component you have to deal with is exhaustion. Whether mental or physical, nobody is able to sustain a continuous fighting mindset. The longer the fight, the higher the odds people will burn out and drop all resistance.
Second component is outing infiltrators looking to do the above and destroy your movement from the inside out.
Third component is avoiding radicalization due to the above as it will turn your movement from a reasonable position to a fringe extreme.
Fourth component is to avoid becoming a cult. Ideas are good, but don't fanaticise over them. Not everyone thinks the same and there's always a conflict of ideas.
Fifth component is understanding that people die and their experience and knowledge isn't inherited in full by the next generation, so avoid gathering around a central figure you can't do without.
Sixth component is to find a way of communicating without communicating out loud. Rather than super secret spy stuff, it means having a set of guidelines for people to follow if things don't go according to plan rather than have them panicking.
Seventh component is having conviction. Don't bother doing something like this if you don't believe in it. Doubt will creep in even when you're wholeheartedly dedicated to something, let alone when you're just paying lip service.
Feel free to change or add as desired.