Take time to propose a counter offer, and don't bargain against yourself by backing down right away.

先花点时间还盘，而且不要和自己讨价还价，马上做出让步。

You have to learn the rules by heart: how to start, pose a counter offer, avoid pitfalls, and make sure everyone is playing fair until the deal is done.

如何开始、提出还价、避免陷阱，以及确保交易完成前每个人都是公平交易的。