Your army Compositions and tactics.

[The Errant]

Medium heavy Epirote stack. Good for just about anything. The Katapeltikai outrange HA so I can use this stack against Armenian and Parthian armies when needed.
I use a heavy stack too where the four Phalangitai Deuteroi are replaced with Pezhatairoi and the two Pezhatairoi are replaced with Chaeonion Agema.
The Classical Hoplites are replaced with Agrianikoi Pelekephoroi. The standard Prodromoi with Thrakioi Prodromoi. The Peltastai with Thakioi Peltastai and one Sphendonetai gets replaced with Thessalian Heavy Cavalry or another unit of Thrakioi Prodromoi.

I use the classical Hammer and Anvil. The Phalangites hold the line while the Cavalry run and charge in the back. The medium cavalry deals with pesky enemy cavalry leaving me free to act against the flanks and rear. They also chase down routed units.
The Elephants are used for flanking and rear attacks against the strongest enemy infantry once the Prodromoi have dealt with enemy skirmishers.
Gaps in the line are plugged, either using the Classical Hoplites or the Illyrian Thorakitai. The Agrinians make excellent assault infantry for flanking. Those AP axes really hurt even heavily armored enemy units.
Peltastai deal with enemy skirmishers well enough. The Thracian variant doubles as very competent assault infantry when needed.
Slingers can move and give supporting fire from an exposed angle. The Katapeltikai can also use flaming ammo against wavering enemy units.
Most infantry based armies don't stand a chance. Full or almost full HA stacks require a different approach in open battle. And a different unit composition.

Standard formation:

----------------------Peltastai/TP-----Peltastai/TP-----------------------

--------------------------Sp-------------Sp-----------------------------

------------PD/Pez-PD/Pez-Pez/CA-Pez/CA-PD/Pez-PD/Pez----------------

Prod/TP---Hop/IT--------------Katapeltikai-----------Hop/IT---Prod/TP---

Thes/TP---Agr--------------------------------------Agr----GB----EI/EKI-