A while back I chanced upon yet another “advice for PhD students” article, which cajoled me into finally writing my own. I should mention that I don't really like this sort of article; as a side-effect of this cognitive dissonance, the text below will be somewhat profane. (Just as many such articles contain unacknowledged US-centrism, so mine contains some UK-centrism. I hope you can deal with it.) Figure out how to make yourself work effectively. If you're relatively young when you start...