You must be polite_your attitude
Answers
Listen and be understanding
If you show other people that you are listening to them, and that you understand them, they will be more willing to listen to you and accept your opinion. Don't just say "I disagree", show them that you are listening and that you understand them before you explain your opinion.
You can do this by using statements like:
Yes, but...
I see what you mean, but...
I agree up to a point, but
For example:
I think we should wait until a better opportunity comes along.
Yes, but we might not get another opportunity like this for a while.
I think we should ask for a 20% discount because it will show them that we are serious.
I see what you mean, but I think 20% might be a bit too much. It might put them off.
2. Avoid negative words - instead use positive words in a negative form
People react to positive sounding words, even if they are used with a negative auxiliary.
Don't say: I think that's a bad idea.
Say: I don't think that's such a good idea.
Let's go for a good cop, bad cop approach in this negotiation!
I don't think that's such a good idea. They might see through it