How can I catch up in Alien Frontiers?
Get lots of dice. Not only are dice resources, but the more dice you have, the more powerful each one becomes. First, you can make better combinations; second, you can gain resources and spend them in the same round without the threat of having them stolen. Usually the sixth die paints a target on you for aggression, but if you're in last place you might be able to avoid that.
Get your colonies down. Until they're all down, you can play with the balance of power all you want, but you can't win.
Look for ways to disrupt your opponents' majorities and solidify your own. This means having alien tech cards with useful secondary abilities that will let you boost your score once you're within striking distance.
Force the second-place player to do the work of stopping the leader. Don't waste your own resources. If the second-place player isn't trying to pull down the leader, you're not going to win anyway, so you might as well play for the case you can win.