Generally it is more effective and you'll get better adoption of your online courses if you focus on a specific result for a specific niche. Broad general topics don't tend to perform well outside the university setting. For online courses it works best to have a clear change that will result from taking your course and give people a step by step process to get them there.
There are a number of factors that increase the effectiveness of an online course from an educational perspective. Generally you don't want to overwhelm students with too much in the way of graphics, audio and text at the same time. Keep things simple. If you're doing video that's a great way but don't add too much animation and text to it. This short circuits our brains and can actually reduce how much we learn.
Motivation and completion is crucial to the success of your online course. If people don't actually take the course they won't learn much and they won't refer others to take it.
There are so many websites all over the internet which offers free courses to you. I would suggest you to go to youtube and subscribe to the channels related to the subject you want to learn. Other than that I'm sharing the list of most popular websites offering free courses. The famous one are like NPTEL, Khan Academy, Coursera, edX and MIT OCW.
Primarily, Columbus International University (CIU) is a visionary 100% online higher education provider which focuses on preparing graduates for careers in business & management, engineering & applied science, liberal arts, creative technologies & science, and open programs. Secondarily, CIU develops any program that a student may wish to pursue but CIU is not offering, excluding some with restriction e.g. medicine, law, etc. through its school of open programs & graduate school of open programs. CIU is pleased to be among the very few to offer 100% online higher education programs to working professionals, executives and mature students in the 21st century. All CIU programs are intensive, fast-paced (accelerated) degree programs and are best suited for working professionals, executives and mature students already working in the field of their study, however, serious students who wish to jump-start a new career may also find our programs valuable to them.