What are two techniques that can be used to compress the Project Schedule?

Crashing - This is a project schedule compression technique in which cost and schedule tradeoffs are analyzed to decrease the project duration with minimal additional cost. A number of alternatives are analyzed, including the assignment of additional resources. Approving overtime pay for project resources is another example of crashing.

Fast tracking - This is a project schedule compression technique used to decrease the project duration by performing project phases or some schedule activities within a phase in parallel that would normally be performed in sequence. For example, testing of a product can start when some of its components are finished, rather than waiting for the whole product to be completed.