Here's one nasty lil creep strategy I used to use in 1.0 (doesn't work anymore because comp can sally forth as many times as it damn well pleases -.-):
1) Divide your army into ten or twelve or more little things on the campaign map, and siege a city with all twelve of them. Build siege equipment if you want, to waste time, but it won't make a difference. Any time the comp tries to counter one of your sieging armies, withdraw, then bring it back in the next turn. By the time the city starves, you'll have conquered it without losing a single man! HAHA!
crazy fun. Here's another
2) Train maybe ten assassins and ten spies, and ship them off somewhere far off away from your Empire. Spy on enemy (or neutral in this case) cities, and build up your assassins' skills. Make sure they're pretty good, and have them attempt to kill off all, if not many, of their family members, even if it means having all your assassins die off. Another faction gone! FWAH!
3) Spy time. If you play as Scythia or Armenia or some faction with great horsemen and crappy infantry, and don't want them held back by slowmoving infantry, have lots of spies travel with them. When sieging a city, put them all in, so the percentage of unlocking the gates increases to nearly 100%. Attack the city with all cavalry and no infantry! HAHA GREAT!
4) Military cities. I use this particularly when playing as Carthage or Egypt (when your capital city has a population growth of like 10% X_X), and your pop keeps taking off and economy going down the cesspit. Have a very young family member be governor, and gather up all the family members with ancillaries that you can into the city. Give the governor all the 10% unit training discount ancillaries you can, including the sweet Decorated Hero. Not only will units come cheap, but their times will decrease! An Urban Cohort could be done in 1 turn!!! For even better results, make sure the religious temple gives bonus to Experience. If you're playing as the House of Julii, use Mediolanium, for their temple to that Gallic goddess of Horses. The Romans love her, and you can build Roman Horse Temples adopted from her, that eventually lead to a +5 bonus to experience in Pantheons. WOOT!
5) Make use of Peasants! If your city is growing too fast and you're building some peasants to lessen the population, PUT THEM TO USE! Rebels are constantly around--use masses of Peasants to take out the Rebel brigands wandering around your territory