Not sure what your circumstances are, but if your doing this for a scenario, you could either make the AI seem more powerful than they are by giving them super attacking immobile units or since the AI is programmed to go after strategic resources give a resource to a certain civ that one civ needs for a unit, building, etc and they will attack them to get it. I also asked this question to a couple of people. There are also a few other things which the AI also respond to negatively (may not be the best word), the AI can act a bit differently to civs in a different culture group. The AI can also act a bit negatively to people that have a favourite gov that is shunned for them.
If you have a preset map that requires building, the AI tend not to attack much if there is still building space, so if you make a big map you should think about this and adjust accordingly the settings and the amount of civs, so the AI will not constantly build. You may even want to make certain tiles unable to build upon.
These are things ive learned after making quite a few scenarios.
Also the strategic resource thing can also work if you dont want a certain civ to attack a civ, but instead you give both balanced resources so they dont need to attack each other to get a certain resource.