Take one cargo hull, add one weapon, and as many sensors and engines as will fit. Proceed to run roughshod all over the enemy by destroying EVERY SINGLE colony ship, constructor, unarmed base, scout, or other unarmed ships they make. Meanwhile run circles around any poky combat ships the AI laughably tries sending after you.
You've hardly tied up any resources and are still expanding at the normal rate, meanwhile this tactic completely cripples the AI, even at high difficulties... and quite frankly has made the game boring. Giving the same tactics to the AI would be making things even worse, but as a fix, cargo hulls really shouldn't be allowed to mount weapons. Either that or just give one weapon to everything (and make one weapon not count in your target choosing formula...this is probably the best solution actually), with your one hitpoint I don't think anyone would bother using this tactic then.
Please fix this Stardock, very cool game otherwise (except for that almost complete lack of tool tips when starting up... I thought I was playing with them off and went into the options to turn them on - to my surprise, they already were on, hehe