How I lost an empire

[Andronikos]

As Baktria:

- build mines, you can become the richest eastern kingdom, conquer India (there are mines too)
- make Saka Rauka and Pahlava your allies (they will betray you, especially on VH, but it can earn you some time and you won't fight all three at one time or it will happen only after you are superpower), don't conquer Antiochia Margiane and Marakanda, it just provokes Saka
- fight against Seleucids first they have better cities, let nomads be, archery duels and steppe battles cost you men and thus money, you need money for mines, battles with Seleucids could be won with minor casualties.
- in cities that are frequently attacked build stone walls, but not the largest ones (with those enemy gets towers with balistae), train huge garrison of slingers and archers, sally in each turn of siege, slingers can kill enemy general from walls, have HAs or skirmisher cav. in cities to provoke enemy to come into range of your archers on walls
archers:

Spoiler Alert, click show to read: 

Persian archers - your basic archer, good range, attack, 25 arrows,
Persian archer spearmen - only a little weaker, but can stand longer in melee, another basic unit, cheaper than previous
Indian longbowmen - powerful attack, sadly few arrows (15), but their sword is a deadly weapon and they make one of the best soldiers in cities defence, they are more light infantry with bows
Subeshi, Persian heavy archers - 35 arrows, very long range, high attack you can get them in northern/southern cities in regional barracks

Your late bodyguards are monsters, they eat hetairoi and Seleukid bodyguards for breakfast, Pahlavan and Saka cataphracts are inferior to them, can cause routing on first charge, especially if you have FM with 50 bodyguards (on large)

You DON'T NEED cataphracts, elephants, elites, train them only after you become rich. Few phalanxes, bodyguards, cheaper HAs, archers, light infantry (baktrian and eastern axemen) and light/medium cavalry (Kambojas, Baktrians) are enough to win early battles

With mines established, India conquered, elephants, cataphracts, guild warriors and elite HAs, you are the greatest and richest empire in the world with unstopable armies.