One way to help the AI greatly, is to play like an imbecile for 30 turns.
No, really, I'm serious. Pretend your empire is being ruled by a royal house suffering from horrible inbreeding. Or communists. Then you stage a coup and you take over and start setting things straight. Now try to win.
Another fun thing to do, is to kick yourself out of office occasionally. Give the AI ministers total control for 1 year out of every 10, representing your fall from power, or sabbatical, or whatever.
Another fun thing to do, once you've established a clear winning position, is to pretend that your ungrateful minions revolt and depose you. Enraged, you take over the biggest remaining rival empire (whose people wisely receive you as their only hope for survival) and vow to take revenge.