For all scientists
There are many resources, just a web search away, on skills you need to be a successful research scientist (often equally applicable to other careers). Below are some we have used in the lab, as well as in Bachelors and Masters courses:
"Ten simple rules" guides on writing, presentations, collaborations, networking and more from PLOS Computational Biology
"Q & As" from Current Biology features informative and inspiring personal career stories and views on topical issues
Tips on making a great poster from Cornell Center for Materials Research
David Stern's frank blog on "How to Give a Talk"
Tips on giving a good scientific oral (and poster) presentation - slides from my own seminar
The 1-hour workday - encapsulates one key way to get the writing tasks done
From William Strunk, Jr. and E.B. White, The Elements of Style: "Omit needless words. Vigorous writing is concise. A sentence should contain no unnecessary words, a paragraph no unnecessary sentences, for the same reason that a drawing should have no unnecessary lines and a machine no unnecessary parts. This requires not that the writer make all sentences short, or avoid all detail and treat subjects only in outline, but that every word tell."