Hey Zetalou! For me, I used to have an experimental channel where it was basically me trying out concepts with a non-pro camera...even though production value sucked, I still kept sharing them around and over a period of about a year since, it somehow amassed to some 3000 or so collective views...although I am inactive there now...
This current channel I'm on on the other hand...I'd like to believe that my videos were pretty professional grade from the start haha so I definitely started sharing them around a lot more! That and I'm also taking Youtube more seriously by uploading at least once a week haha. Problem is reaching my target audience outside of my immediate friends, which is mostly teens to young adults haha...that and there's no real subreddits that would really work for my types of videos
Long story short...I promote straight from the beginning XD