i got into animation in i think 2014. prior to that i had been making live action short films with my friends, but after college everyone moved to different states and it became impossible to keep making movies with them.
at some point i watched that south park documentary Six Days to Air and was like "hey these guys can do crappily animated 20 minute shows in a week, i bet i could do 2 minute crappy animated shows in a week."
and so i sent out lines to my friends and did most of the voice acting myself... the episodes were indeed crappily animated. but i posted a new one every week.
that built my audience from 0 to about 74 in two years lol (the first year was spotty with uploads but the second year was weekly). I've since removed the animation from my channel.
animation wasn't my forte tho, and i ended up switching from making animations to writing text adventure games, which apparently was more my strong suit. that bumped me from under 80 subscribers to over 400 in a little over a year.
i can only make guesses as to how to build an audience but i would say it came down to 3 things for me:
1. finding a style and topic that i could pour my whole self into and was excited to work on every day, which created a better product
2. post consistently. people follow creators who create. it's not worth following someone who only makes one video and then disappears for 2 years. animation is tough but find a way to post something every day- WIP, a blog entry, a short video documenting your day, etc. That'll give people a reason to follow
3. interact with people and don't be a dick! you gotta respond to EVERY comment you get. some comments are just random internet browsers who comment on everything, but your interaction could change them into a follower. especially comment on the negative comments- just ignore the hurtful tone and use it as an opportunity to crack a joke or invite the person to continue following. I've gotten a surprising number of follows from people who initially left unkind comments, and who (i assume) are generally ignored online because they act like complete asshats. but if you respond with kindness and show you care, you'll find that a lot of the time they just wanted to be heard, and the fact that you were listening and responding with kindness catches them off guard and sometimes wins them over to your side simply because you're the only one who paid attention to their silliness
that's all i got, hope there's something useful for ya