What kinds of measures are most likely to immediately speed up Project Accomplishment?

The following measures are most likely to speed up Project Accomplishment

1. Focus on activiteis which are on Critical Path

2. Focus on activities which can become critical path if there is a slight delay in them

3. Crashing of activities

4. Analyzing project schedule and identifying opportunities for parrallel work without cost increase

5. Ensuring availability of all resources at job site and

6. Others.....