It's slightly hard to spot a manipulator, which is why they're the hardest type of person to deal with. Normally, when there's a manipulator in your office, you get the feeling that something isn't right, but you can't quite put your finger on it.
Manipulators use all kinds of tricks - sarcasm, false praise, being indirect - to get you to do what they want you to do.
Think about it, is there someone who alway says: "You're so good at this, no one else can do it like you"? Or, when you're trying to make a decision, do they say: "No one else will agree with you."? They might well be a manipulator.
How to deal with a manipulator
Once you've worked out that you've got a manipulator on your hands, they key is to (calmly!) question what they say. So, for example, when they say no one will agree with you, ask them who has told them that they won't agree?
Another tactic is to acknowledge their point of view, but then tell them what you think. So, you might say: "I appreciate that this is what you think, and some people might agree, but I think that..."
With a manipulator, it's best to be direct, that way they'll realise you're not a push over and hopefully it will make them less likely to try it again in the future.
Or, if you're feeling really brave, you could just tell them what you're thinking - in a polite and controlled way, of course (especially if it's your boss!). So you could say: "Rather than hinting that you’d like me to do something, I’d prefer it if you ask me directly.”
That way they'll get the message that you've sussed out what they're up to!
But remember - while you can ask someone to act differently, you can't force them, so don't be surprised if they fall back into their bad habits. In that situation, the best thing you can do is be aware when they try to manipulate you, and decide what you want to do.