I find that the beginners guide to the specialist economy, written by JackOfClubs, is a very good one to begin with.
I'm an average Monarch player, and have some problems with military units management.
I made some experiments at emperor level following what he suggests in his guide and obtained very good results, especially in terms of military flexibility.
One thing I did was to make SE games on great lakes maps (small size, and duel), in order to better understand the deep mechanics of a SE game played with Gandhi, and also in order to be sure to get Pyramid and/or Parthenon and/or GL in the same town, which is not compulsory for winning but helps a lot

!!!. Of course, I'm sure you can't do all those wonders at higher levels, since you have more urgent things to do than buiding all this wonders, and also because the AI builds much faster than you; try, try again, experiment...
If you're a peacemonger (like me, some months ago), I'm sure you will soon become an early warmonger playing this kind of game, thanks to the flexibility you get with such games.
If you want to understand how it works, you can also learn a lot from succession games played SE style in this forum.