Negotiation business: What are the things you should never say while negotiating?

Thanks 

I think it is : something about my last experience for the same subject of negotiation 

You should not disclose the real and real money to complete the commercial transaction and not disclose the real price of the asset or goods to be sold or bought or purchased

While you are negotiating with your business be sure that you show more respect and convince them how to be part of your business