The best training I ever had was being made to write the news in briefs while working on a weekly newspaper. Each one had to be exactly 30 words, regardless of how simple or complex the story was. If I handed in 31 words it was sent back and I had to do it again. I hated it at the time but it's excellent training - really teaches you how to edit, to explain things clearly and simply, and tighten your writing. I think every writer should go through it (and not just so they can share my pain).