How to be a good negotiator

A bit about my understanding of good management: A manager needs to guide you, not tell you how to get there.

For example
if I tell you:  Get me that jacket, i think  you will think of me as an arrogant prick.
If I say: Get me that jacket because I am cold, you may think, its a burden but he is cold so I will get it.
Both cases are manipulation. In the first I am being dominant and ordering you, in the second I am pulling on your heart strings and making you force yourself to get that jacket.
What I think I should say as a good manager is:
I am cold. Then a good man and a good friend will offer me a jacket. Also manipulation intended in this case, but only to draw the "good" out of you.

I believe this applies to all things in life including negotiations at high levels on serious topics.