Your aim for this lesson is to identify what people in your chosen niche are interested in watching. Don't be tempted to guess your audience's interests. Your decision to create a video should be based on the view count of similar videos on YouTube.
Don't be inclined to recreate or copy an existing YouTube video. Instead, use the title as the theme for your own video. You are far better off adding your own personality and ideas in a video than trying to replicate an existing one.
Use the alphabet soup method described in this lesson to create a list of video ideas and list them in a spreadsheet. Ideally, you want at least 30 but 50 would be better.