Find your niche partners, collaborators, and champions: As you’re creating your course, look for notable people who are also creating content in the space. Look att how their businesses operate and incorporate that into your own plan. You can also reach out to any influencers and make them affiliates for your own course. This way, they’ll be incentivized to share your content with their own audiences (which can be a major way to generate your first sales—it helps if you're using one of the best CRMs for small business—and start building your own community!)
The topic you choose must have enough depth that you can create a lot of content for it. This is important for building an authoritative site, for search engine optimization, and most importantly, for the end user. If you don't have enough content about a topic, you're not going to be taken very seriously as an authority on the topic and it's unlikely you can convince someone to make a purchase from you.