I read a wonderful book about the '6+1 writing traits.' Here's a link to more info:
http://www.nwrel.org/assessment/definitions.php?odelay=0&d=1but there doesn't seem to be any 'approved' 6+1 website that I can find. There are plenty out there. What I like about 6+1 is that it indroduces a vocabulary about writing that you can look at the works of professional writers, and have a good conversation about them, or use it to talk reasonably about a child's writing sample.
When I was a kid, my feedback about writing consisted of 'copy editing' type of stuff. This is important, but has almost nothing to do with improving communication on paper.
Just having a vocabulary help tremendously.
Best Wishes,
Grinity