KISS. 

In general, written feedback is most effective when it is timely and brief.  Long written responses by a teacher may be useful for some students, but will be skimmed or ignored by many.  In general, the more you write, the less likely it is that they will read it. Given the amount of effort and time required by teachers to respond to student work in writing, this method is inefficient on both ends.  When complex ideas need to be communicated, conversations are much more effective than written comments for most students. Fortunately, open work time creates opportunities for such conversations.

Feedback trains your students in metacognition. 

When your students are given feedback regularly, it helps them develop a clear sense of whether and how well they have mastered the material.  It should be done with the intent of training them to internalize a sense of excellence.

Feedback takes courage. 

The giving and receiving of feedback can make students feel vulnerable.  When a student discovers she did badly on a test, her initial reaction may be one of shame, sadness, or anger, all of which preclude learning from her mistakes.  She is unlikely to get good feedback from you or her fellow students when all she wants to do is bury the incriminating test in the bottom of her locker as soon as possible.

This kind of response comes, in part, from a judgmental posture towards making mistakes, and especially from failing at anything. Unfortunately, this attitude can be deeply ingrained, since it is regularly reinforced by the habits of doing school; if success means getting good grades, then failing a test is a disaster to be avoided at all costs.  The fear of failure can drive students to cram more diligently before a test, but also trains them to be risk-averse and sets up a counterproductive attitude about learning from mistakes.

Students must therefore be trained to understand that making mistakes and learning from them are essential components of the learning process.  Mistakes can be seen as clear and useful information about what a student hasn’t learned yet and still needs to work on to be successful.  This shift in perception can only occur when the classroom culture is grounded in a better understanding in how learning actually works, and in replacing the old habits of doing school with the common goal of self-directed learning.

Feedback can also be frightening for a teacher as well.  Asking for honest responses from your students about the changes you are making in your practice can make you feel vulnerable.  You may be afraid that students will take advantage of your openness to criticize or attack you. However, even such abuses can provide teachable moments about the nature of effective feedback and how a community works.  By honestly and dispassionately responding to a student’s inappropriate remarks (no small task!)56655, the whole class can learn to distinguish between useful and hurtful criticism. Drawing an analogy to an art critique can also be helpful.  The aim of such feedback is to help the artist see her work through the eyes of others, with the common purpose of improving everyone’s skill as artists.

It is important to confront such fears directly.  If you want to change your practice, there is no more important factor than listening to how those changes are perceived by your students.  Just like an architect who tries to design a hospital without ever talking to doctors, nurses, or patients — it is simply bound to be less effective to design a class without student input.  

On the other hand, you need to be comfortable with the pace of change and the level of exposure you feel in how you handle that change. Taking on too much perceived risk is as counterproductive as being overly cautious. Finding the balance is key.

What is needed to allay these all these fears of students and teachers alike is a bedrock sense of trust within the community.  That is why it is so important to create a classroom culture that requires true mutual respect from every member.