Cease & Desist--10 Bad Twitter Practices to be Stopped Immediately! I agree with all except the bad language thing... *whistles innocently*
C. Hope Clark: A Writer is Multi-talented, Multi-directional. Don't limit yourself, peoples!
The Passive Voice: Constructing the Narrative Arc.
Mediactive: Author's To-Don't List. I would add--don't make a big honkin' using the wrong word error in a Author's To-Don't List, but that's because I haven't had my coffee or my Zoloft yet this morning. Still, good advice. (Extra points if you spot the error and post it in the comments.)
Carina Press Blog: Angela James: Don't Turn Your Passion Into an Obsession. Advice on avoiding burnout.
Livia Blackburne: Showcase the Sexy, but Don't False Advertise (and other lessons I learned writing my book pitch). Self-explanatory.
The 99 Percent: Op-Ed: In the Particular Lies the Universal. About finding the power of your own gifts and voice.
OpenForum: 11 Radical Slogans that will Change Your Business.
Copyblogger: The 5 Keys to Content Marketing Mastery. Applies to any sort of writing. Or other ventures, for that matter.
Write it Forward (Bob Mayer): The Kernel Idea: The Alpha and Omega of Your Book. Aimed at NaNoWriMo-ers, but solid advice for any writing venture.