Ohh, and if you attack a colony that appears empty, check their stats. They can show some off information, but you can usually use them to tell if your enemy still has units or not. More specifically, look at the # of units he has recruited, and at the # of units he has lost.

it is not accurate vault, the units he has lost sometimes larger than the units he recruited. Simply becuz all alliance loss on a joint battle with him participated are counted. So sometimes he will have larger unit loss than unit recruited.

that's why its only best used at the beginning of the era or with new players

I say make a lot of spam in the beginning of the round. Attack any colony that is not defending themselves at all as well as most all the mines you can reach within 12 ticks. (any farther and someone else can get them)
after that defend those mines with your life xD they give score now so keep em
The biggest tip I have is just stay as ACTIVE AS POSSIBLE in the beginning of the era. If you cant then dont expect too much from the era. The era is based off of your start basically, or random wars that bring everyone around you down and you up. (but lets not think of it that way
Really, just get a good start and you are set
once you get a good start, good alliances recruit you, you get good boosts from the alliance and you are SET

hope it helps (even though a lot of strategies have been said before me) ;/

-Kentaro