Just downloaded and started playing.  Looks pretty cool so far.  Seems like a mixture of a few other games I've played with a Star Wars twist.

It's definitely an addicting game model. 

Well, the low hanging fruit are the missions and the planetary competitions. Problem is you have to attack to get in on those.

You'll want to at least do your daily defenses. They are a money suck if you are lower level.

Keep asking for defenses. I'll provide when I see them.

I'd try to beef up the armory. You'll get bonuses that overpower certain units. Keep a good defense and remember to flip for your attacks (it is a relatively new feature so I am constantly forgetting to do that myself).

The game gets impossible at higher levels. You can't earn enough to get your upgrades and attacks take a significant chunk out of your funds. But it has its moments.