I also have my own idea on how they would do so. Being a big fan of the Warhammer 40.000 universe, I'll take two very different examples.
On the one hand, we have the Tyranids, which are basically giants swarms of insectoids creatures obeying to the Hive Mind.
Their main strategy in war is the good old mass assault tactic, sending millions after millions of small sized creatures to overrun most defences. But, it is not the only thing the Hive is using. There are some bigger creatures, used as walking tanks to destroy heavy fortifications, there are also tunneler creatures, flying ones, and all sort of things. So the mean they have on the battlefield are pretty common, the biggest difference is that these soldiers will never surrender, they will also never flee if under control. Meaning they will take enormous losses during any fight.
But how could they sustain that much losses ? Mostly by quick breeding and gestation. Another interesting thing is that most of these small soldiers can't eat. They got claws and fangs and mouths but do not eat things. Thus, once the fights is over, the smaller beings come back to somekind of gastric acid pit where they'll be digested and their biomass will be sent back to a ship, ready to be used to produce new warriors once more.
So, their soldiers are definitely reusables and don't have any word to say about it, apart from the bigger ones which have somekind of autonomy.
The most interesting thing with them is probably how they manage to maintain a link between them. The Hive mind needs somekind of relay to reach all of its minion. These are the most important creatures in the swarm, while these creatures are present, the small minions obey without a complain and everything is alright. But once these creatures are dead, the link between the Hive and the minions is cut, thus disrupting them greatly. It's generally a good way to deal with these creature, kill every Hive Mind relay, and the swarm will be quite easier to deal with.
These relay are also a strength as much as a weakness, for instance they allow some elements of the swarm to act independently, as infiltrators or assassins.
The second case in that universe is the one of the Necrons. Some might argue they do not have a real collective consciousness, and they are right, nonetheless they are using a lots of robots, and their base soldiers though they were human once, are now machines which must obey to their Overlord.
So for me it's quite like a collective consciousness in the fact that every Necrontyr apart from the high command will have almost no free-will and will mostly obey to any given order.
While the Tyranids fights in a very bestial way, with basic strategies from a predator hunting its prey, Necrontyrs are far more evolved and tends to use the fact their soldiers are soulless, emotionless and can react at the speed of a quantum processor to build powerful strategies.
Apart from the fact they master an impressive military technology (hey guys, look look we have the power to turn a star into a supernovae !) their tacticians can count on an impressive level of coordination. Even though they could gather in impressive big blocks of soldiers they tend to be organized in units, somehow inspired by the roman legion system, with centuries, cohort and legions.
Taking advantage of the fact they're mostly machines, their plans are made in multiple dimensions, using complex mathematical / physical concept, to the point the only other race that can really surprise the best Necrontyr strategist are the Orks since they are so dumb and acts in such an irrational way that their moves can't be predicted by science.
When facing Necrontyrs, you can count on enemy reinforcement joining the fight at the exact moment needed, and when seeing their soldiers withdrawing you can assume it's part of the overall plan.
Lastly, their soldiers do not have any voice emitters or stuff like that. So they're fighting in a perfectly disturbing silence, broken only by the sound of their weapons. Afterall, why would these minions with no will need a way to communicate by voice ?
I hope it'll help you creates your own Collective Consciousness and make it ready for war.