I started posting in May of this year, and reached 1k about halfway through June. Idk, im still floored. I have virtually 0 following anywhere else, so it wasn't like I could direct traffic to my comic that way. I think it came down to two things:
1. GL isn't nearly as popular a genre as say BL or general Romance, so maybe I had more visibility with an audience hungry for GL.
2. I started posting a mermaid centric comic during Mermay, so maybe readers were more open to reading my comic at the time.
I think in my case and many cases, the growth comes down to dumb luck. I feel really lucky anyway
Also, I was and remain enthusiastic about my comic and stuck to a schedule, which I think goes a long way in pulling people in.