The AI is incredibly stupid. Don't lie and just make the highest legitimate bid you can based on your own dice. If you have to raise, do so as little as possible - like, if you have two 6s showing and the current bid is two 6s, only raise to 3.
The opponents will generally make ridiculous raises and, if you're playing against more than one guy, one will call the other out. And once you knock out a couple of dice from the AI opponents, they seem to get even more stupid, to the point that they sometimes make bids that are impossible to be true.