How do you get more followers for your subreddit?

I created a subreddit a few weeks ago, I don't have enough money to promote it through ads. I invite many people to join my group everyday. That's too tired. Also, I was active in some groups with my official account.
How do you guys get many followers in short time?
Thanks

Find subreddits filled with people that are looking for the type of content that your subreddit offers, create better content than the one on that sub, crosspost and invite people from said sub

Find bigger subreddits of the same niche, get popular posts from that subreddit, repost on your subreddit, crosspost back to the original subreddit.