These are links to websites and articles that I have found helpful.
Grammar Girl: http://www.quickanddirtytips.com/
Grammar Underground: http://www.grammarunderground.com/blog
Merriam-Webster Dictionary and Thesaurus: http://www.merriam-webster.com/
Grammarly.com Blog: http://www.grammarly.com/blog/
Grammarly.com Handbook: http://www.grammarly.com/handbook/
Copyediting.com: https://www.copyediting.com/
Writers Write: http://writerswrite.co.za/
http://writers-write-creative-blog.posthaven.com/
http://the-plain-language-programme.posthaven.com/
References to almost anything: Dictionaries, encyclopedias, thesauri, and much more http://libraryspot.com/
Behind the Name: the Meaning, Etymology and History of First Names http://www.behindthename.com/
CIA – The World Factbook: https://www.cia.gov/library/publications/the-world-factbook/
British Slang Dictionary: Helpful when Yanks attempt to write British dialogue. http://www.peevish.co.uk/slang/
Urban Dictionary: Updated frequently http://www.urbandictionary.com/
Society of Professional Journalists: http://www.spj.org/
Writer’s Digest: http://www.writersdigest.com/GeneralMenu/
Poets & Writers: Contests, MFA Programs, Agents & Grants for Writers http://www.pw.org/
Association of Authors’ Representatives, Inc.: http://aaronline.org/
Editorial Freelancers Association: http://www.the-efa.org/
American Copy Editors Society: http://www.copydesk.org/
Mystery Writers of America: https://mysterywriters.org/
Sisters in Crime: https://sistersincrime.site-ym.com/
Private Eye Writers of America: http://www.privateeyewriters.com/