Usually, it depends on the niche and the volume of the keywords you are targeting. As per my experience here are the following aspects:
1. Your channel must have at least 100 videos for a decent start. Later minimum 10% videos must be gone viral if your content is engaging or niche is popular.
2. Video on-page should be perfect like keyword in the title and video name must contain keyword in it
3. Relevant tags preferably follow your own as well as competitor tags
4. Proper description or even something relevant to keywords
5. Try to buy views in a start, if any of your videos go viral it will bring you views on other videos too.
6. Create backlinks not much high quality but decent backlinks are enough but its optional as a final step.
