here what i written in another post like this:
The tip i give to everyone in my squad is: you can buy the planetary comm when you are a level 5 and unlock any planet you want, but don't go there untill you are strong enough to fight levels 9/10 and get at least 1 battle star for a victory, or you will be smashed and will lose too many medals. If you don't care for victories or medals, go and try take out some big guy full of resources for your upgrades. Anyway, be patience and have fun.
I will add only two things: the "could not find an opponent" (or just CNFO) is what is killing the game on Windows, on every planet unlocked you will have this message all the time and get stucked for so many hours, maybe one or two days, until you find a rival or a rival you can win, and not a beast at level 9 or 10. The second thing is search for a big squad at least Level 36 with the Perk World Relocation Cost unlocked. At level 36, it will save 2 battle stars, at level 38 it will save 4 battle stars. Things will be more easy and you don't have to pay crystals only to move to another planet.
Leader of AndroidsDream Squad on Windows. Empire Level 10, 45k medals, Rank 16.
Level 9 Imperial on vacation!
Level 9/8/7 Rebel player in "Solo's_Band" Level 50 Squad (Join us and war everyday!)