Life Buildings

1) Altar
2) Tavern
3) Castles of Chaos, Death, Nature, and Might.
4) Beastmaster (provides a free starting combat skill)
5) Combat Academy (I made up the name; it gives 4 random combat skills)

I'd add that I find developing Life quite difficult because there isn't a strong, impactful unit or combination, and there isn't a powerful hero (like a Chaos Knight or Barbarian). In my opinion, Life units always need support from their mage, and tactics are important; they depend heavily on this. Also, a mage of Order in the army would be very useful.
In principle, you can get by with archers (ballista) at the beginning, but your speed will suffer.