At the AHA’s website, there is a worthwhile article by Laura J. Mitchell on the need for historians to write well. That should go without saying, but unfortunately it needs saying! Here’s a snip of the piece:
Just because writing is too rarely a topic of professional development does not mean the majority of historians want to write and read unwieldy books or stifling papers. We all aspire to write good books with clearly written prose that advances a coherent argument supported by well-documented, transparent use of evidence.