Getting YouTube views but no subscribers - what would you change?

Some videos get views but very few of those viewers become subscribers. If that is happening, what should a creator look at first? The type of content? The audience being attracted? The opening of the video? Consistency between videos? A reason for viewers to return? If you have experienced this and improved it, what changed? If you are currently facing the problem, tell us your niche and what you have already tried.