Best Practices for Teaching Online

Video Software - Be sure to try out different video software and find what works best for you and your students.
Troubleshoot - Don't try to teach an online class for the first time with a student. Expect there to be hiccups and a learning curve, so spend some time using the software and practicing a lesson with a friend or colleague. This way, you can get some great feedback on things like sound quality, lighting and how you come across via video.
Use Screenshare - Consider any teaching tools you might be using and learn them ahead of time. You can learn to do a screen share if you'd like to show a short video clip, share a PowerPoint, or model an online activity.
Send Instructions - Send detailed instructions in advance of the first online lesson to guide students on how to log in and communicate expectations. You may even want to send a video of you talking while showing them step by step how to log in.
Plan B - As with any technology, there may be hiccups. Plan ahead. Do run-throughs with a friend or colleague, so you can hopefully troubleshoot how to work through any issues before they happen with students. For anything you can't predict, do the best you can and have a backup plan if something isn't working.
Record the Session - Make sure to record the session. You'll want to send the video out after the lesson so students can refer to it as needed. For classroom teachers, this means students who were unable to attend in real time can still participate. For private lessons, this means they can go back to find answers to questions they have while working on the subject alone. You can even go back and re-watch yourself and look for ways you can improve the experience.
Use a Wireless Mic - If you plan to be writing on a board at times or moving around at all, consider grabbing a wireless mic that will catch what you are saying clearly, whether or not you're facing the screen.
Start a Blog - Rather than sending separate emails, start a blog that is password protected and give all the students the password. Post all instructions, how-to videos, recorded sessions, and anything else you need to communicate as a separate post on the blog. That way, if they need to go back and reference something, they don't have to dig through 500 emails to find it. This platform will also make it easy for you to integrate new classes since you'll have the previous blog posts. You can either just update the date on the posts so they show up on top for new classes, or you can group blog posts into categories for easy navigation.

Expectations - Just like a traditional classroom, you'll want to have clear expectations for the session. You can communicate this in the way that works for you, either in a nice email beforehand or with a quick presentation at the start of the session. Consider things like how to participate, how to comment, how to create a learning environment (put barking dogs in another room, try to find a quiet place without siblings around, turn on lights so you can see them, silence phones, etc.)
Enthusiasm - Be sure to smile and talk enthusiastically. You won't be able to use a lot of body language and motion to convey ideas, so make sure your facial expressions and mannerisms are positive and excited. Remember that students will respond to and feed off your energy. If you look uncomfortable and shy, they will respond likewise. If you look like you're adapting and having as much fun as possible, they'll relax and join the fun, too.
Stay Still - Try not to get up and walk around and move a lot. This can make it difficult for students to hear you clearly. Unless you are wearing a wireless microphone that will pick up your voice wherever you go and you feel that moving around is important to teaching your subject, it's best to stay in one place and focus on teaching.
Take Questions - Ask students to submit questions on the messaging function of your video conference app or send in comments if you are live streaming. You can also set times to respond to questions during the lesson. If this is a private lesson, you can answer questions verbally back and forth as you go, but if you are working with a group or class of students, you'll want to allow them to send in questions as they have them. Then, dedicate some of the class time at the end to answering those questions.
Routines - Set up routines for the online class so that over time everyone knows what to expect. Perhaps start and end the class the same way each time. Post a simple agenda behind you and go over it before you begin. Or, have a fun chant you all do together to get everyone engaged.
Audience - If teaching to a blank screen or to a group of kids who won't turn their cameras on is messing with your groove, set up your own "audience" and teach to them. Put some stuffed animals or action figures in seats in front of you so only you can see them. Imagine they are your students and you are teaching to them instead. A big part of teaching is performing, and online sessions will put this skill to the test more than ever before!
Get Creative - Dig deep and look for ways to make online lessons memorable. Can you dress up in historical costumes that match the time period you're discussing? Can you make changes to a set behind you that will keep their attention? Can you wear a silly bow tie, a funny hat, or do something else that will get them focused right away? Can you tell stories and jokes that will make students relax and feel comfortable? Remember that "stories stick and facts fade," so look for creative ways to deliver lessons so they can't wait to log in on time.
Check In - Make time to check in with students in smaller groups or one on one. These meetings don't have to be every day and can just be 15-minute sessions, but will help develop and maintain a strong student-teacher relationship and encourage students to stay motivated.