Not too deep but here's what works for me:
On hard, found your city and start buiding warriors, nothing else. Explore around getting other units and citys from Ruins. Bump into another Civ ( Always the Americans! ). Concentrate units, attack, destroy, conquor city then move on to the next fat American city. Research ballistics, get Archers, then research Monarchy. Americans plead for peace, trade them a cease fire for their map, then attack them again. Wipe them out, you want their citys. All citys building either warriors, or Archers on a 2 to 3 ratio. Bump into some one else...repeat above. Only fight one Civ at a time. After Monarchy go for gunpowder, cannon making then rail road. You may then have to improve your goverment due to the number of citys (nearly all except the original conquored ).
In my last game I never terra formed ( okay only a couple of farms ) except for building roads, forts ( so I could build more roads ) and rail roads, always toward the enemy.
In SMAC I always ending up sooner or later (mostly sooner) in a war with every one at the same time. In CTP2 in maybe the 8 games Ive played the other Civs stand by and watch you exterminate them one by one. So its easy to concentrate all your forces on one victim, one city at a time.