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."
Creating clear and informative image-based figures for scientific publications - from Helena Jambor et al. in PLOS Biology