I just... keep going. Knuckle down and keep on trudging.
I know I have a bunch of subscribers on Tapastic now, but I've done my time posting art to nothing but the sound of crickets chirping on Tumblr. I know what it's like to share your work with the world and get nothing in response.
It's tough, and it wears you down, but if this is really what you want to do, you have to keep going. The only way out is through.
And take those few subscribers you have as signs you're doing something right. No matter how few they are, they're precious! They mean something! They mean that you've reached someone, and that's all we're really here for, as storytellers. Someone is listening - better keep telling the story!