Heather Johnson, over at bootstrapper.com has assembled a list she calls The Top 100 Freelancer Blogs. There are 16 blogs for freelance writers here, including The Golden Pencil and some other favorites, as well as some that are new to me.
But the rest of the list is well worth exploring. There is, for example, a section just on Copywriting and Marketing, another on Design, etc. etc. You get the idea. I suggest you explore the list a bit. I have a hunch you’ll find at least one or two you want to bookmark.