New popular science book: 'Grip op je aandacht'

Stefan shares 49 advices to achieve optimal concentration. What are the basics? What is 'flow' and how do you get there? 
The book covers all ins and outs and do's and don't with regards to concentration. A practical guide (with exercises) on why scrolling through your phone does not count as break, how you can use drinking coffee to strengthen your concentration and why daydreaming is for the good cause.