I uploaded the video in June and I forgot sent backlinks for a little while but then stopped(I dont remember why). The video has decent amount of social shares, views, and likes. However it only has about 300 backlinks and it is ranking 5th for a keyword that gets 7,000 searches. My question is should I start building links to it or should I not fix something that is not broken and let it be? If you think I should start building links, how many per day would be enough?