As a traditional classroom teacher I use feedback as follows:
1. Written note on assignment- I write above the grade so the student reads the message and it catches their attention as to what I am trying to convey as my feedback to them.
2. Sticky Note- occasionally I need to give feedback to a student but to avoid embarrassment I give them a sticky note which are usually very attractive sticky note with my written feedback on it.
3. Feedback conference- I have a conference with the students usually during class time when they are engaged in work time. The conference is just a few minutes and I hold them in the classroom.
As an online instructor I would:
1. Audio file- include an audio with the assignment that I am giving feedback.
2. Digital Images- I would send encouraging digital images.
3. Email- I would simply an email with feedback.