This is something that many of us had a problem with — You’re waiting for an email from someone, and a day passes since their latest reply. Anxiousness, rises, another day passes, oh my god! Now theories start developing, and those theories can lead you to your downfall.
This is due to the difference between your relative experience of time, and their relative experience of time. To them, because they are less invested the the days go by much more quickly. For you, you think about the event more, so your days go by much, much slower.
For more effective negotiation, aim to be just slightly faster then the other person. This takes the benefit that you will be moving things forward, but won’t sabotage yourself by trying to move too quickly.
How do you speed up your relative experience of time? Create other things to think about. When your waiting on action from other people, ask yourself if there’s anything else you can do. If you can, start working on that, and this will push them to respond faster anyways. If there’s nothing you can do in that campaign, do things that will increase your overall strength. If you’re in a negotiation with a consulting client or employer for example, and there’s nothing more you can do but wait, just coding on OSS projects is an excellent use of your time, or learning a new skill.