Cambly recommends giving roughly 1 correction every 5 minutes. As your student speaks, you'll notice errors and have suggestions for better words or phrases he could have used to express his thoughts. Some tutors like to give corrections on the spot, while other tutors prefer to wait until the student has finished his thought. You may want to experiment with both approaches before finding your personal style. Tutors have found that giving too many corrections may hurt a student's confidence while giving too few slows the student's learning. We find that a good rule of thumb is 1 correction for every 5 minutes. For example, if a session is 30 minutes long, you should make roughly 6 corrections. See "Best Practice Videos" for real examples of corrections.
When you provide a correction, you should do so verbally and type the correction into the text chat box. We automatically tag the point in the video when you enter the correction. After the session, your student will receive an email report of all your comments, each of which links directly to the point in the video where you made the correction. You can access all of the corrections you've made for each student in the Call Log of your History tab.