Karen,
You are right on when you discuss tone as a factor in feedback. It's important to start with something positive, but still give constructive criticism to help students grow from the process.
Setting up a schedule is great for online learning. I tell my students they will get feedback on discussion board postings within 24 hours, but many graded assignments take more time. But, I always let them know when they can expect your response.
Rubrics are very helpful sto students can evaluate their own work before turning it in. And, you can be more consistent in your feedback… >>>
