How can we compress a schedule in project management?

By applying one of the following three techniques..

1) optimizing activity lead-lag times,2) fast-tracking critical path , and3) crash the critical path.

There should be two ways of doing it as under:-

1. Develop three types of project plans, one is Pessimistic for customer, second is realistic for your management and thrid one is optimistic for your team. The project estimation should be between realistic and optimistic so that any slippage can be managed within it.

2. If above is not possible as per your organization requirements then optimizing activity lead-lag time and adjusting resource utilization to100%