Scheduling the amount of time needed for a task

Hi!!! I love the idea of not giving too much time to complete each task to prevent procrastination etc . I tend to add a lot of cushion time. And I do find that confusion, procrastination, and lack of focus at a certain point does tend to set in, even though I get the job done.

BUT I found when I put less time for each task, I feel a lot of pressure and it feels tight to get everything done. How do you suggest I schedule? I do want to double my productivity.