A short article by Professor Max Abrahams that argues conventional wisdom is wrong and tactics like leader decapitation do not help:
http://politicalviolenceataglance.or...tional-wisdom/

Increasingly, empirical evidence has revealed that terrorism is a remarkably ineffective tactic for groups to induce government concessions. ...What I found is that groups are far more likely to attain their demands when their violence is directed not against civilian targets, but military ones... the attacks on civilians actually lower the odds of government concessions.
Referring to another article in a journal he explains why this happens:
It turns out that certain kinds of groups are significantly more likely to attack civilians than others – those suffering from leadership deficits in which lower level members are calling the shots. Leadership deficits promote terrorism by empowering lower level members of the organization, who have stronger incentives to harm civilians.
The journal article is openly available on:https://www.academia.edu/5365151/Exp...h_Phil_Potter_