5. Keep your hands clean

If your boss is fired and you get the job, you want it to be because you are really the best person for the role, not because you played politics. And if your coup fails, you don't want to find yourself on the unemployment line.

One way to minimize evidence of your involvement is to avoid leaving a paper trail. "Never anything over e-mail. Never," says Korn/Ferry's Rubenstrunk. Or, as the turn-of-the-last-century Boston political boss Martin Lomasney is said to have advised: Never write if you can speak, never speak if you can nod, never nod if you can wink. "If you put anything in writing, assume your CIO is going to see it," says Heller.

Also bear in mind that career paths often cross multiple times. "You want to make sure your boss doesn't turn around and say you betrayed him, because you will rely on him later on in life to give you good recommendations. And before he leaves, he's going to ask you what role you had. You're going to want to answer him honestly," Heller says.

Heller offers this example: Say you and your boss have always been at odds over a decision to outsource. In internal IT discussions, you go on record as supporting outsourcing, while he still refuses to look into it. Months later, a new CEO comes on board and asks you to join him for lunch. He asks you your opinion on outsourcing. You answer candidly — which eventually leads to the CIO's ouster. When you have your final lunch with that CIO and he asks you whether you pushed him out, you can be honest about your differences without seeming underhanded.

Or at least as if it's nothing personal. It will have been, after all, a business decision.