hoplites and falankes

[Fridge]

I think you've answered your own question - don't attack from the front!

Best way, IMO, is to weaken them with skirmishers (they're very slow when they're in formation, so javelin and even pilum throwers can get plenty of shots off) or missile troops. If you can get a unit of javelin throwers in behind them, where they're less protected, you're in business.

Flanking and rear attacks are the best method, and the best way to do that is to pin them from the front with an 'expendable unit' (sometimes a skirmisher unit set on loose formation can slow them down long enough without taking too many casualties), something cheap, and then hit them in the sides or rear with something - infantry, cavalry, or at a push, those skirmishers you were using to soften them up.

Don't be scared to run away, either. If you've got aline of legionnaries set to fire at will, let the phalanxes advance while you unload on them, and at the last minute, pull your line back, reform, and repeat to fade. If you can't run for whatever reason, you can slow them down using legionarries on fire at will and guard mode - you won't lose as many men and should buy yourself more time to flank.

But ultimately, from behind and from the sides...

Oh, and Siris, it's cavalry, not calvery. Get it right.