It's always a difficult line to walk between sparing a child his feelings and letting him know how you honestly feel about his accomplishments. I still haven't mastered the nuances of this skill, but lately I find I'm being much more critical of student work at the fifth grade level, in part because if the bar is kept low then children may not bother to climb any higher than they have to, particularly if they've been conditioned to a climate of teacher say student do type learning. Of course, I'm speaking generalities, and always about published work, projects, journals, essays, and not the type of work
children do on worksheets and with other mundane activities.
The problem is, many children are proud of their finished activities and projects and published works. No matter what the teacher thinks these little boys and girls are so happy to have accomplished a feat. They haven't learned to look at their work objectively. But, teachers have to train them to be critical of their own finished work and the only way to do that is by putting it all out on the table for them (along with great model samples, projects....for them to measure their own accomplishments against). That is not to say a teacher should degrade a child's proud accomplishment. Yet, a teacher must first tell the child what he likes about his project. For a teacher to say that he likes the whole project top to bottom with no other feedback will send up a red flag to the student anyway. They know full well when they are being given false praise.
After describing what you like about the project, journal, published work, take a minute to explain some of the things you would like him to, in the next project, make improvements with. "I love the story and the pictures are nicely illustrated, but I think the cover art might have looked better if you added more color and spent more time on the lettering." "I'm glad you are writing your reading reflections each day, but I think you can write more than two sentences each day. Next time I want you to add more detail." "I'm sorry, but you'll have to redo this project because we can't have a poster on display with misspellings. Always check with the teacher and do your original designs in pencil, have them checked, then go over them in marker." "I like your handwriting in this letter, but there aren't enough details included. You need to add more information."
First honoring what the children have accomplished then going on to explain where you would like to see improvements sends the message that although they have accomplished something, they're work is not beyond reproach. How can children go from A-B if they have nothing else to reach for? Constructive criticism is necessary.
Where writing is concerned I tell them how the real world of writing and publishing works. This helps them, at this age, to understand where I'm coming from when I review their writing, in particular.
Of course, you always have children who try to skate by and put out trash not because it's where they are on the learning landscape, but because they don't want to lift a finger for fear it might move a pencil. In these cases, I typically point out
more things I don't like than things I do. They need to know that their pride and work ethic is on display with their work and it's up to them to rise to challenges and fulfill their potential. That still is constructive criticism, but more of their work ethic than of their work.