Before negotiating with other parties, you should know the minimum requirements you must get after the negotiation process is over. That is, the number or condition that you must defend desperately, of course in a fair way.
Negotiating well requires a preliminary evaluation to determine the condition. NEVER negotiate without knowing what number or condition you should get. If you already know it, you will know when to say Yes or No to all the possibilities that occur.
Examples are like when you want to buy meat in traditional markets. The money you have is Rp. 100,000 and you have to buy 1 kg of meat and other kitchen spices. However, the price of meat per kg is Rp. 100,000, which means you have to bargain at least Rp 90,000 for meat to have the rest of the money to buy spices.
If the seller agrees with the price you are offering, your negotiation is successful. If the seller does not want to lower the price, which does not match the minimum number you want, you can switch to another seller