YouTube comments are often disparaged online for their poor quality, but for the entrepreneur, they can often be a great source of viewers. Engaging with the community and answering their questions will go a long way in promoting your brand.
Try to answer comments made on not just your own videos, but also videos on similar topics made by other vloggers.
For example, if you sell fitness accessories, find videos on fitness and diet related topics and respond to comments on them.
Don’t push your products aggressively. Instead, drop hints that the commenter can learn more about the topic on your channel. Remember: your first task is to be helpful. Selling comes much later!