empirecitizen

Started 1.2 with Core World too.
There's a rather easy, although a bit exploitative way of defeating the rebel fleets...
Spam Skipray blastboats, nothing in the starting rebel fleet can handle a tight ball of 20 skipray squads.
Upgrade to MKII for more speed and concussion missiles, that should be more than enough to give you time to start churning ISD II.
Or... More skiprays if you like

I must say the ground combat is great. I already like the imperial blitzkrieg.
Using AT-ATs as spear head to take out armored units and AT Turrets(X3 light turbolasers are very powerful indeed) . Then send a sweeping AT-ST charge to break soft targets. Finally drop the stormtroopers from the ATAT for mopping up and capture. Repair and repeat. Add bombing runs and planetary bombardments when needed.
I haven't ran into serious air resistance yet so the AA walkers are not in service yet.