Although this question has been asked few years ago, it is still relevant for many hew PhD students. Therefore, I suggest that you, the new PhD student read carefully the following documents available on the section "Resources" of the "PhD Candidate" page :
"How to Get a Ph.D." by Estelle M. Phillips ;
"Choosing Your Thesis or Dissertation Topic" (U. of California)
"How to Succeed in Graduate School: a Guide for Students and Advisors "
Happy reading. Although this question has been asked few years ago, it is still relevant for many hew PhD students. Therefore, I suggest that you, the new PhD student read carefully the following documents available on the section "Resources" of the "PhD Candidate" page :
"How to Get a Ph.D." by Estelle M. Phillips ;
"Choosing Your Thesis or Dissertation Topic" (U. of California)
"How to Succeed in Graduate School: a Guide for Students and Advisors "