Consider the personal reasons that led you to buy this book. How would you assess your visualisation skills, your interests in this subject and maybe your role or duties? What help are you seeking and what do you hope to achieve? What aspects of your visualisation capability do you feel is most lacking? This kind of personal assessment will help frame your focus during your reading of the book and offer a means of assessing the value of the book once you have finished it.
Assignment Link: http://book.visualisingdata.com/chapter/chapter-1