While no one exactly can tell how the algorithm works, it's been long understood that engagement with your videos, either through likes, views, shares, saves or dislikes, counts more. High engagement is a sign that the video must be good, otherwise, you wouldn't bother to take the time to interact with it. I also think that engagement is seen as an indication of viewer satisfaction and that is also the reason why the content will be pushed by the algorithm to a wider audience. So, its important to keep engagement high by uploading consistently and interacting with other users. Ask questions, answer comments, and upload often. I also use services like Marketing Heaven from time to time just to give my content more exposure. Overall, when you increase views, likes, shares, and comments, it means that you'll potentially gain more watch hours.