The hoplites kept a very standard set of tactics when marching into battle. They would line up on the field each army on opposing sides and then they would march or possibly charge into battle. Obviously there was variation, but they kept to this very simple style of battle when it came to the phalanx.
During the Greek civil war, however, certain commanders began to innovate the role of the phalanx on the battlefield. The Spartans were the first to begin to tamper with innovating the phalanx. Their main contribution was to slowly move towards the right side of the field during an advance. They noticed that hoplites on the far right of the line had the tendency to drift to the right, so they utilized this to their advantage. The Spartans strategy was to move far out to the right flank allowing them to wrap around the side or even rear of the enemy, thus hitting them where they’re least defended. This saw success at the Battle of Nemea in 394 BC. The Spartans crushed the Athenian forces via their flank and reorganized to defeat the Thebeans on the other side of the enemy line, earning themselves the victory.
The second major innovation was made by a Thebean general by the name of Epmainondas. To counter the Spartans, he deepened the Phalanx on the left side of the line and angled the right side of the line during the approach. This allowed the left side to engagethe Spartans before they had a chance to flank the Thebans. It also allowed for more defense in case the Spartans actually did manage to out-flank them.
This strategy saw great success at the Battle of Leuctra in which the Thebeans are recorded as “pushing back” the Spartans (Lungbill, 52). This innovation would allow Thebes to defeat the Spartans and secure dominance over the Peloponnese Peninsula. These small, subtle changes would greatly influence the history of phalanx warfare. These very changes were observed and studied by the then Thebean hostage, Philip II of Macedon. He would come to use them in his conquering Greece and his heir, Alexander the Great, would use them build the largest empire the world had ever seen up to that point.