Excellent written communication skills are essential in the workplace. There are many resources to improve business communication skills that will help you recognize common grammar problems; use proper tone, active or passive voice, and concise, clear language; organize information and compose and edit your writing.
Recommended books:
The Elements of Business Writing: A Guide to Writing Clear, Concise Letters, Memos, Reports, Proposals, and Other Business Documents by Gary Blake
Business Grammar, Style & Usage: The Most Used Desk Reference for Articulate and Polished Business Writing and Speaking by Alicia Abell
Effective Business Writing: A Guide For Those who Write On the Job, 2nd Edition Revised And Updated by Maryann V. Piotrowski
Business Writing, Period. by K. T. Maclay
The Business Style Handbook: An A-to-Z Guide for Writing on the Job with Tips from Communications Experts at the Fortune 500 by Helen Cunningham
The Elements of Style, Fourth Edition by William Strunk Jr.