Enter the grammar guide. These handy little guides can help you through some of the tough questions, such as comma usage, pronouns and the proper use of apostrophes. After my dismal failure, I immediately went out and bought an AP Style Guide 2011 to help me polish up my skills. While this has helped me tremendously in writing for the places who follow Associated Press style, there are many other styles to be followed, and each mill and client may follow different procedures.
Overall, I would say the AP style is the most popular, so if you can choose only one, get the AP Style Guide. It costs about $20 and is worth every penny. I keep a copy by my computer all the time, so I can quickly research the proper usage of words. I was dinged by an editor for saying “Washington state”. Their suggestion was “Washington State”. Using my AP guide, I was able to point out that capitalizing “state” only applies when referring to the university. My grammar guide is a valuable tool, and one I suggest every writer pick up.