Aliens Early Game?

Ok I understand the early game of the marines. That being you want most of the guys moving out in groups on west and east side of the map claiming as many resources as possible. You probably want 1 or more guys at home base building the armory.

I don't quite get it for the aliens as to me it currently feels like I just run out as a skulk almost at random till you find a place that the marines may grab then ambush them?

Thanks