These are the best proven used factors to rank your videos on YouTube.
Best Top YouTube Videos Ranking Factors 2019
Average view duration for all videos on your channel
Top videos or channels listed by watch time
Audience retention data for a specific video for different time frames
Relative audience retention for a video compared to the YouTube average for similar videos
Engagement in first 30 minutes
Subscribers – after watching a video
Thumbs up/Thumbs down
Positive sentiment & engagement
Broad match keyword targeting across title, description, and keyword tags
Go with my YouTube Training session for more details.