Depending on the online classroom version you use, you may only have the option to have one student speak at a time. This can be useful, especially if you have one student that dominates the class. Give each student an opportunity to contribute to the discussion, answer a question or participate in an activity in another way. For example, have students take part in a role play. Using your ability to "turn off" other students, have one student play part A in the role play," and when he is finished, "turn on" a second student's ability to speak to have him play part B.
Create a part of your lesson to have a student answer a question and then ask another student in the class the next question. For example, student A might read, "What do you do for a living?" in a lesson about jobs and careers. After answering the question, the student then asks the next question on the list, "What do you want to do for a living?" Students then have a chance to practice both reading and forming sentences conversationally. The teacher also serves as a guide and does not lead a lecture on the topic. Students are more in control of their learning, which makes it more interesting and memorable.
Instruct your students to write on the board at the same time if you have an exercise in which students fill in blanks or match words or pictures. They answer the questions they know the answers to, thus saving time from having one student at a time try to answer a question. This is a useful technique mainly for upper level students who will understand the instructions and not be afraid to write on the board simultaneously. It works well for smaller groups as well. Go over the answers when students are finished answering the questions.
If the teaching platform you use has the capability to use the Internet, insert pictures or hyperlinks to pictures of words students do not understand on the board. If you have extra time at the end of class, watch videos online related to the lesson or have students read supplemental material and discuss it. Ask your students if they can see the webpage on their ends as sometimes technical problems prevent them from doing so. You might be able to save a picture to your hard drive and insert it as a slide into your teaching program for the student to see or copy and paste text into a slide or into a document to upload to the lesson if this occurs.
Body language is important in communicating information. Use your webcam whenever possible to demonstrate an idea to your students. If they are having a hard time understanding your pronunciation of a word, for example, show them the object you are saying if it is on your desk. You can also use facial expressions to demonstrate emotions or to show students they have answered correctly or they should try again.