ISIS is resorting to unconventional warfare and making use of whatever resources available including modified trucks laden with explosive designed with bulletproof shield to get close to the enemies as much as possible. the surprise element is the suicide squad to take initial lead to remove the perimeter defense line n create as much collateral damage as possible before the next wave of main battalion takes over.
in defense mode, they deploy snipers and again mines and IED. aerial attacks by russians were generally responsible for up to 60% of the equipment losses suffered by ISIS.
it is not without flaw. they lack aerial support and lacks heavy artillery shells. the suicide squads were lead by experienced fighters with a group of mainly new recruits strapped with body explosives whom can be sacrificed.
the kurds and yazadis are now deploying similar fight methods with aerial support that is able to thwart many of the ISIL attack including the latest from the reclaimed SINJAR.
the popular mobilisation forces formed from iranian henchmen and loose confederation of xtians, shite, etc does not have such aerial support hence are not able to engage decisively against ISIS. also, the foot soldiers were not well trained nor coordinated, except for the elite commando teams.
the hebollah has been in cahoot with iranians to fight against ISIS and FSA for a long time and mind you, 4 top iranians has lost their lives.
hard reality - rather then being pussies and using precision attack, the russian method being crude would probably save the day. just get rid of the media and deploy more cluster bombing, thermic bombs in no hold bar as per rules from sunzi art of war. rule no. 1 there r no rules.