How were Greek armies organized

Hoplite The hoplite was a small infantryman, the central element of warfare in Ancient Greece. The word hoplite (Greek ???????, hoplites) derives from hoplon (?????, plural hopla, ????) meaning an item of armor or equipment, thus ‘hoplite’ may approximate to ‘armored man’. Hoplites were the citizen-soldiers of the Ancient Greek City-states. They were primarily armed as spear-men and fought in a phalanx.
The origins of the hoplite are obscure, and no small matter of contention amongst historians. Traditionally, this has been dated to the 8th century BC, and attributed to Sparta; but more recent views suggest a later date, towards the 7th century BC. Certainly, by approximately 650 BC, as dated by the ‘Chigi vase’, the ‘hoplite revolution’ was complete. The major innovation in the development of the hoplite seems to have been the characteristic circular shield (Aspis), roughly 1 m (3.3 ft) in diameter, and made of wood faced with bronze. Although very heavy (8-15 kg or 18-33 lb), the design of this shield was such that it could be supported on the shoulder. More importantly, it permitted the formation of a shield-wall by an army, an impenetrable mass of men and shields. Men were also equipped with metal greaves and also a breast plate made of bronze, leather, or stiff cloth. When this was combined with the primary weapon of the hoplite, 2-3 m (6.6-9.8 ft) long spear (the doru), it gave both offensive and defensive capabilities.
Regardless of where it developed, the model for the hoplite army evidently quickly spread throughout Greece. The persuasive qualities of the phalanx were probably its relative simplicity (allowing its use by a citizen militia), low fatality rate (important for small city-states), and relatively low cost (enough for each hoplite to provide their own equipment). The Phalanx also became a source of political influence because men had to provide their own equipment in order to be a part of the army.

The Hoplite Phalanx

The Hoplite Phalanx of the Archaic and Classical periods in Greece (approx. 750-350 BC) was a formation in which the Hoplites would line up in ranks in close order. The Hoplites would lock their shields together, and the first few ranks of soldiers would project their spears out over the first rank of shields. The Phalanx therefore presented a shield wall and a mass of spear points to the enemy, making frontal assaults much more difficult. It also allowed a higher proportion of the soldiers to be actively engaged in combat at a given time (rather than just those in the front rank).
When advancing towards an enemy, the phalanx would break into a run that was sufficient enough to create momentum but not too much as to lose cohesion. The opposing sides would collide viciously, possibly terrifying many of the hoplites of the front row. The battle would then rely on the valour of the men in the front line; whilst those in the rear maintained forward pressure on the front ranks with their shields. When in combat, the whole formation would consistently press forward trying to break the enemy formation; thus when two phalanx formations engaged, the struggle essentially became a pushing match, in which, as a rule, the deeper phalanx would almost always win, with few recorded exceptions.