Ok you need light + heavy infantry in equal proportions, your general (or other heavy cav), two or three peasant units (yes, peasants) and two or three archer units (not essential if you‘ve got plenty of infantry)
First start with lining up your main force of inf as heavy inf light inf, heavy, light etc and put your peasants ahead of your main force and to the flank. put your general quite far behind the peasants. if your peasants reach the flank of their lines quite far before your inf (keep away from the phanalaxes) their general will attack the peasants, your peasants can completely swamp them, but will, of course be losing. While the general is held in place, storm in with your heavy cav or general and kill the general. By this time your infantry should have reached the enemy line. This is where your archers come in. Put them on fire missiles and concentrate on one unit at a time. This will make them turn and run. When you’ve killed off a few units, put your heavy infantry on the phanalaxes, and move the light infantry to their flanks or rears. As phanalaxes are very weak on the flanks and rears this will be easy. All that’s left is to kill the missile units (which is never hard).
THIS IS TRIED AND TESTED (used it to kill the Macedonian’s faction leader)
Ps- Its often a good idea to have a bit of light cavalry to chase the enemy down at the end. (even missile cav will do)
Pps- for the general killing bit, if the ai sends more cavalry than the general, send some heavy inf with the peasants.