Deemphasize the grade while emphasizing feedback!
Don't confuse assessment with grading. Assessment refers to coming to know: learning what students can and cannot do. Grading is placing value on where they are in their process. It's about judgment while assessment is about understanding.
This article by Margie Krest is old but still relevant.
Sarah Zerwin and her colleagues in Colorado have been wrestling with grading or, more specifically, not grading:
Check out this link to the Teach Thought for an article on reducing the time we spend grading writing.