In the Iliad, Homer finds a great tool in the simile. Just by opening the book in a random place the reader is undoubtedly faced with one, or within a few pages. Homer seems to use everyday activities, at least for the audience, his fellow Greeks, in these similes nearly exclusively. When one is confronted with a situation that is familiar, one is more likely to put aside contemplating the topic and simply inject those known feelings. This would definitely be an effective tactic when used upon the people of Homer's day. From the heroic efforts in the Iliad itself it is clear that the populace of his time were highly emotional creatures, and higher brain activity seems to be in short, and in Odysseus' case, valuable, order.
It is also wise to remember that history is written by the winners. In the Iliad, there seems to be relatively little storyline from the Trojan's side. We are regaled with story upon story of the Greeks, their heroes, and their exploits, while the Trojan's are conspicuously quiet, sans Hector of course. It could almost be assumed that throughout time most of the knowledge of the battle from the Trojan side had been lost.
Considering the ability to affect feelings with similes, and the one-sided view of history, Homer could be using similes to guide the reader in the direction of his personal views, as happens with modern day political "spin". These views that Homer might be trying to get across might be trying to favor Troy. It could easily be imagined that throughout time, only great things were heard about the Greeks mettle in war, and that Homer is attempting to balance the scales a bit by romanticizing the Trojan peoples, especially Hector, and bringing to light the lesser-heard tales of Greek stupidity. Shortly into Book Two, Agamemnon gives the speech to his assembly about his plan to rally the troops with reverse psychology. Agamemnon shall announce he is giving up on taking Troy, whereupon the individual army captains will then "prevent their doing so." When the announcement is made, King Agamemnon is startled to see the ranks, not surprisingly, take advantage of the chance to leave and make for the ships with vigor. Homer describes the scene as "bees that sally from some hollow cave and flit in countless throng among the spring flowers, bunched in knots and clusters..." This simile is tainted with dark words like "from a hollow cave" and "bunched in knots", giving the "bees" an ominous tone. The Greek ranks are painted as a throng of weak-kneed wimps with their constitution sapped, obviously not the case as they go on to win the war, but it suffices to cast the Lycians in a negative light.
A short, but emotionally appealing, simile is found after the Greek warriors have changed their mind about leaving and return to the Scamander: "They stood as thick upon the flower-bespangled field as leaves that bloom in summer." This scene assumes quite a juxtaposition. A flower-bespangled battlefield? This is perhaps an attempt to show the absurdity of the Greek army, changing positions from fleeing to brazenness as flowers are to the field of death.
Near the beginning of Book Three a group of elders of Troy, not fighting material, but skilled orators, are found resting on the tower "like cicadas that chirrup delicately from the boughs of some high tree in a wood." The cicadas song and the "tree in a wood" cast memories of repose and relaxation, rest and peace, which are then injected into the "delicate" elders. Another attempt of Homer to cast the Trojans in a favorable light.
Later in the same book Ptolemaeus is Homer's vehicle for putting down the Greeks again. Upon seeing shirkers of the front line of battle he likens them to "frightened fawns who, when they can no longer scud over the plain huddle together." Undoubtedly, the men of Homer's time hunted...