Doing a PhD is a singularly personal pursuit, and fields differ greatly in their standards, but a common factor is often the ease with which a student can become overwhelmed by the magnitude of the task at hand. This often makes it hard for them to take a pragmatic approach and keep some distance between their project and their identity/self-esteem.
Back at the dawn of the Internet, when I did my PhD, my supervisor gave everyone a much-circulated copy of his rules for PhD students. While I was a group member, I took it upon myself to convert the document into an electronic form more easily distributed.
Most of the advice is quite sensible and pragmatic, but is biased in some cases as a result of a perspective that is:
Here’s the document: Pratsinis Group Guide for PhD Students