[BigDisAwesome]

You got it Gandalf, astral gem search along with a little bit of utility just in case you gotta send those mages out there early.
If I'm not being rushed and have secure borders, I normally prefer to get thaumaturgy, conjuration, and evocation all to 2 to start site searching. Then get construction up to 6, maybe even 8 if there's nothing I immediately need out of the other schools.

Site searching is key I think. The earlier you find a magic site, the more gems you make of it. And if you happen upon a really good one, it can change your whole game or strategy. Namely if it has a good recruitable, has a nice magic school bonus, or if it can summon troops when you send a mage into it.