If you haven't read Chris Brogan's blog or heard him speak, you definitely should do both at your first opportunity. I saw Chris speak back in 2009 and he really helped me "get" what social media is (and isn't). I'm not sure which specific blog posts of Chris' I read about writing and content marketing. But there are two pieces of advice from it that I use every time I write or edit content. And being a content marketer, that's an area where I spend a lot of time.
1. Delete words.
This is basically the 'less is more' philosophy. If you can say something thankfully, powerfully, and beautifully in less words, do so. If you want to approach deleting words a bit more systematically, you might want to look at your word count in your Google or Word doc and set out to decrease it by 20 percent. If you've written a 300 word blog, try and take 60 words out of it. Your writing and the points you make with it should be tightly woven.
2. Read. A lot.
Read like you need to read to survive. Read like the words in books are your food and water. Or beer and cigarettes. Or whatever sustains you. The more you read, the better you tend to write. You assimilate different techniques and approach to crafting a story or making a point when you read. I always try to have 2 or 3 books I am reading at any given time. And, in my experience, read what interests you. It doesn't always have to always be marketing related.
So thank you Chris. I know you said this differently and better (and with less words) but your advice stuck with me. And it's advice I use every day. And I hope it's advice that other marketers and writers can use when creating content, too.