This is a very insightful post!Start initially by involving yourself with other peoples chats and communities
Whenever anyone comes to your channel leave a reply to their comment and visit their channel. It is not an obligation to subscribe unless you like the channel genuinely but do watch and leave a message always.
Watch other people's content and leave a quality comment showing that you did so.
They may start to visit your channel and would most likely leave a comment too, people go through comments and will note the way you engage.
Don't leave a heart only as a reply
Ask a relevant question if necessary when anyone replies.
This worked for me and I was spotlighted by another source for high engagement .