Cvijetic recommends setting up "buffers" for all your important deadlines, meetings, appointments etc.

Having a buffer is really just a solid time-management technique. Although I wouldn't call it a "productivity hack" per say, I do think it's just smart time management to set realistic schedules and timelines for all projects, appointments and meetings so that you don't become comfortable with running over time in your meetings or missing deadlines on important projects. I will be making a conscious effort over the next few weeks to insert "buffer" zones in my calendar.

How it works in practice:

Say you have an important meeting scheduled for 3pm. In your calendar, schedule it for 2:45pm. Just to be safe. Or if the project deadline is 1.7.2016, set the deadline in your calendar for a couple of days before, 28.6.2016.

This becomes your failsafe way to ensure you're always on time, and that you always meet your deadlines.