I have heard about online teaching?

I am in fact teaching online at wiziq.com. I am a freelance tutor. My subject is Physics and I teach high school students. I fix my own charges and schedule classes at a mutually convenient time. I have learnt about these on my way. You can also join tutoring companies and work for them. For contacting them you may search on the net for such companies. I had experience of classroom teaching also. if you need any further help you may get in touch with me (mail ID sengupta.kajal@gmail.com )

The rates you could earn really depend on the subject and the quality of your materials.

For example, some courses could be free or introductions, with the aim of guiding students into your paid courses. Courses can range from physics, maths, or teaching english online. Other options are niche courses like localised tax rules, advanced javascript, accounting or every more specific (e.g. how to knit a flag).

Once you decide on your course, then you need to determine the type of materials that you are willing to provide. Do you want to upload lectures or teach in real time (using something like skype)? Do you want to create lecture notes or just assist with students current study challenges? Do you want to create tests or study aids?

There are lots of options and as you work out your strengths, I'm sure you can have a great additional income teaching online.

Best of luck.