Resources are a writers best friend. Whether they are printed or online, you need resources to back your work, check your spelling and make sure your content is really your content. Check out some of these resources for freelance writers I have compiled over the years.
(Notice a thin list? That's because I'm still working on it)
Books By Your Desk at All Times:
Merriam Webster's Dictionary
AP Style Guide
Home and Garden Resources:
"Good Housekeeping" Magazine
"Real Simple" Magazine