Some of it is more appropriate for American grad students with their longer periods and higher courseloads (and of course they’re called “graduate students” rather than “postgraduate students” as they are here in the UK), but, coming from another astrophysicist/cosmologist, most of the advice is right on and I certainly will commend it to my own students.
I’ll point out that one of the pieces of advice isn’t to please your supervisor. Our job as a supervisor is to turn students into good scientists, and that means that, especially by the end of your PhD, you ought to be working with us rather than for us. Of course, the hard part is to make sure that you have a good enough relationship with your supervisor that you feel comfortable disagreeing with him or her. This is probably easier in my sort of small-group one-on-one science than in big laboratory-based work in which you’re all working together towards a very specific goal. But even there, your project is your project and you should “own” it, as they say on talk shows and self-help books.