1- Create videos that stand out from the crowd. Content is everything
Don't upload lots of videos, instead, Make each video wonderful. Plan your content and then shot.
2- Be consistent - Upload videos every week
I have seen some channels who have not so good contents, still, they make it happen with time. Just because they were consistent.
3- Always put a note about your next video
What's next is something that will induce your viewers to subscribe your channel for next update.
Good luck.