There are two distinct military strategies that the Achaeans employ to reduce their losses at the hands of the Trojans. The first would be the fortification of their camp by building a wall around it. The second is the involvement of Patroclus using the armor of Achilles to slow down the advance of the Trojan soldiers.
In the first strategy, the duel between Hector and Ajax is inconclusive and does not bring any results regarding the war. The two opposing groups decide on a truce to bury their dead. While the burials were on going the Achaeans took the opportunity to build a wall around their camp. When the war resumes the Trojans fight valiantly forcing the Achaeans back. It is the fortifications that they made during the burial period that saves them from the Trojans subsequently reducing their fatalities and casualties.
"Hard by the funeral pyre we will build a barrow that shall be raised from the plain for all in common; near this let us set about building a high wall, to shelter ourselves and our ships, and let it have well-made gates that there may be a way through them for our chariots. Close outside we will dig a deep trench all round it to keep off both horse and foot, that the Trojan chieftains may not bear hard upon us.”
In the second strategy, the Achaeans are losing again and this time it is worse because the Trojans breach their walls. Nestor meets Patroclus and asks him to bring Achilles back to the war. Nestor tells Patroclus that if he fails to bring Achilles back, he should borrow his distinct armor and pose as Achilles himself. This would help them gain some time and reduce their losses as they reorganize.