I personally feel it is best to create a good quality paid course and get engaged paying students many of whom will then buy your next (and subsequent) related paid courses. If you don't have an audience anywhere online already to get those first few sales I would start building this as well so that once your course launches you have an audience to tell and you can give them discounted access.
You want people to know you are knowledgeable in your field, so it is helpful to engage meaningfully in groups and forums demonstrating your knowledge and helpfulness. Have a Facebook page and YouTube channel as a minimum so that you can be helpful and occasionally share updates about the course you are working on and getting ideas and input from followers and can then let them know when your course is ready.
My first course I launched I had an aim which was to try to get 30 paid students onto my course within 30 days to demonstrate to Udemy algorithms that it was worth promoting my course and showing it higher in search results. This has been my aim with all courses since then that I have published, but it is easier after the first course because if the next course is relevant to those students and builds on what they have learned then many of the students who are on the first course are more likely to take the next course and future courses.
My experience is that many people who get a course for free don't pay attention to what the course is, they signup because it is free and may become paid in the future and they may want to take it but then will have missed out. So it is common to get lower ratings because students then start the course and find out it doesn't deliver what they would like it to deliver. It is common for very few of the students to ever start the course and many of the students who signed up to the course because it was free aren't those who are willing to pay for courses, so when you convert the course to paid and then try to market your next paid course to the students a very low percentage of them decide to pay for the course you are offering.
That isn't to say the strategy doesn't work, it is just not one I use. If your free course can get enough students then even a very low percentage of these becoming paid students on your next course can be good.
What I would be interested in, and hopefully someone who has used this strategy replies with their answer including this information, is how many free students would they recommend you need to have before converting the course to paid and directing people to your new paid course? I would assume it must be in the tens of thousands range rather than low thousands to make it work? Obviously, it would vary depending on the topic and the demand etc.
All the best
Dan
