We raised our first 8k subscribers all by ourselves without ever being promoted. (We received our first promotion in the ‘binge worthy’-list shortly before we reached 9k. I remember that because I was really confused about the sudden surge in subs and even asked where everybody all of a sudden came from xD)
Back then you could only have one category to put your comic in (we were in Comedy. Nowadays it’s Drama/Comedy)
We achieved the 8k by constantly updating, cross promotion and social media promotion.
My second comic was promoted two days after I posted the first three episodes. I assume because we have a good track record with the other, still ongoing, comic. But also because it was a popular genre (comedy/romance) and with a popular element (cat girls).
I don’t want to say the more persistent you are the more you snowball for sure. I mean, there are a lot of old and long comics that never got a bone tossed.
But in our case being persistent was what helped us grow and eventually getting noticed.