According to John Hattie's meta-analyses studies, feedback has a very strong affect on student achievement. In fact, feedback had a 0.73 effect size from his studies. When done correctly, his studies have shown that feedback is crucial to student achievement.
When giving student feedback, you must know your students. Some are fragile and you'll have to be very gentle when giving feedback at first. Other students may seek more feedback than they need at the moment. Choose your words wisely. Do it one on one. Make it level specific as all learners are not the same. Other than that, here are some of my favorite tips on giving feedback:
A. Make it specific. "You broke apart 77 +37 and modeled it perfectly with Base 10 blocks. You then wrote a word problem. It says, 'Bob had 77 marbles and he gave away 37 marbles. How many marbles does Bob have left?' I see your problem written as 77 + 37 and your answer was 114 which is correct. However, your word problem doesn't match that. What should you do?" The important part here is to wait on the student and not tell him what to do. If he sees his mistake, great. If not, he needs to ponder his mistake on his own or confer with a partner. Before he leaves, complement one more thing like I like the way you're taking responsibility for your work by spending time seeing what's wrong with your word problem.
B. Make it timely. Students need and deserve prompt feedback. It's unfair to them to be unaware of what they're doing well, what and where they need to make adjustments, and where they have misconceptions or are just struggling.
C. Ask the right questions to help students reflect. What has been easy for you? Where is the difficult part? What questions do you have? How does your work look in comparison to __'s? What's your next step?
D. Conference, Post-It Notes, Journal, Flipgrid, Google-Docs, Paper/Pencil, Assessments, etc.
Feedback doesn't always have to oral. I do recommend if doing it orally, have the student take notes to document the conversation or points. Just remember to be specific. Be positive.
This is just the beginning of feedback. I'm beginning to notice more talk about student feedback in journals, my PLNs, and in professional books. It's a very exciting time to be a teacher. It should be the best time ever to be a student!