Tactics are designed to lower the expectations of the other side.  Expectation setting is key.  Setting your expectations high, while lowering the expectations of the other side.
Top 5 tactics are:
Deadline pressure
Competition
Changing specifications or influencing specification
Depending on buyer or seller side
Use third parties
Bosses, spouses, “ghosts” that aren’t at the table but somehow influence the final decision
Using levels of authority