In Galactic Conquest it can be frustrating to play the game as Empire (Rebel AI on hard) because you constantly feel on the back foot and its like playing wackamole because Rebels can pop up anywhere and everywhere.
Indeed, I often ask myself "what is the strategy of this game when you play as Empire?"
It's very hard to answer because basically the Rebellion more or less sets the agenda and you respond, especially early-game.
The following observations apply (correct me if I'm wrong):
* Do not overconcentrate forces as Empire. You need 3 or 4 fleets at least on large maps.
* Using Bobbafett to keep Rebel heroes out of the game is critical. That way there's a lot less of those annoying Rebel raids.
* Never ever ever
leave a planet land garrison empty. Space yes, as its more expensive. But stormtroopers and other land forces are cheap. Make the Rebel scum bleed for their victory
And when you can afford it those turret complexes are really worthwhile investing in.
* Use the Emperor in combat mid to late game. At first you need the Emperor to keep those production costs down in the early part of the game when money is tight, but if you get into a strong money position, he is a valuable asset in land battles (yah a bit risky but he's fun to use and worth about 5 units!)
I'm not a great player but these are my thoughts thus far.