Your house rules for EB

[Mediolanicus]

I think my main rules would be

1 Every army must be in a city, in a fort or laying seige during winter (or summer in arid regions) when possible.
2 Take it slow, don't blitz the map and don't blitz your enemies in war. Only attack when you have a reason (AI always attacks you so there's no shortage of reasons).
3 Use balanced armies. Don't spam slingers, archers, elites, heavy cav,...
Between 8-14 units per army. Full stacks are only allowed in emergencies and the additional units must be levies or cheap mercenaries.
For example: my 2 newest armies in my Romani campaign.
My consular army: General, 1 Velites, 4 Hastati, 2 Principes, 1 Trairii, 1 Pedites Extraordinarii, 1 Equites Extraordinarii.
My Illyrian/Greek army to fight Macedonian fullstacks: General, 2 greek levy archers, 2 Akontistai, 3 Illyrian Thureophoroi, 3 classical hoplites, 2 Illirian Light Cav.
4 Disband your armies in peace time, except for a small defensive force.
5 Use levies as garrison troops.