Comments on Writing

I really like it when teachers give a lot of feedback on anything that I write. Of course, it is always nice to have good comments on papers, but writing well is definitely a process (one that I suppose will never end) and teachers are in a position to help that process along.
The most effective things that teachers can do is to address all aspects of the piece. I always wonder if there was something that I was not sure about and the teacher says nothing about it. Does that mean that I did it right? Does that mean that the teacher just didn't notice? I want to know about the organization, errors, and themes. I spend a lot of time considering all of these elements while I am writing, so it only seems fair that the instructor spend some time addressing these things. I don't really know that I ever get enough feedback to improve my writing. One thing I know I never hear is praise for any strengths that I may have in my writing. Teachers never tell you that.
Something that absolutely drives me crazy is if there is nothing on the paper but a grade. I also really don't like teachers using check marks for errors. It's confusing! I guess all in all teachers don't really comment on my papers because they spend more time on students that need more help. If you are a "good writer", it seems like you get to a point where you are pretty much on your own.