[jaif]

This really depends on nation. The only rule that I've found over all nations is "when in doubt, research". By the time you reach the part of the game where that rule breaks down, you know why you are breaking the rule.

For ULM, for example, you want conj 3 and evo 4 as quickly as possible for summon earthpower and blade-whatchacallit. Those two spells turn your smiths into combat machines against large armies. After that, construction is your main priority.

But other races are totally different. They may vary also depending on your pretender. You really need to research your race, find a few spells that you want to cast, and work from there. It's really a matter of experience, I think.

-Jeff