How to grow a subreddit?

Every other subreddit I come across gets 5k-15k subscribers in the first week after its created. I can only grow mine about 500-1k more subs if I happen to get a front page crosspost; which is about every few months. It took my main sub almost a year to hit less than half of what most communities reach in a week or two.

Any advice or suggestions?

Most recent example: r/EverythingFoxes vs. r/furfoxsake