Oh also, DO NOT let eliminated players continue to diplome. They have to go home if they choose to talk about the game. This is the fair way to do it for a number of reasons, but one such reason is that if you lied to say, England, who is now out, and you want to use the same kind of lie on France, France should not know about it unless England told him about it while he was alive.
That's more of a house rule though, I guess.
But imagine this. Say you are the unpopular winner and the two powers opposing you have finally gotten their acts together. That means they have four other "advisors" standing around them giving them tactical advice, intentionally isolating you, using peer pressure to prevent others from diploming with you... it can be a very toxic and unfair atmosphere, so if you have any say in it, prevent this sort of thing from happening.
But it's best that you mention it BEFORE the game begins so that you cannot be painted as having a conflict of interest.