This is a wonderful subject and I hope I can help out. With my comic, and my direct experience, I've learned it's all about quality. More than anything else. If your audience is shrinking/slowing down etc., it's probably due to quality. Either the art, the writing, something is not blowing people's minds enough to get them to come back.
We work really hard to make every page better. I'm constantly trying to refine it. Basically, if you can't get people talking about it or sharing it without your direct intervention or asking, you need to go back to the drawing board. Otherwise, you will be perpetually pushing a boulder up the mountain.
I grow very, very weary of other comics with just a few pages getting 'featured' or becoming an editor's pick, as well. But hey, that's their prerogative. Effort doesn't mean much, trending does. You get trending by word of mouth and people being interested in the comic. You get that by having unmatched quality. Yeah, some comics seem like they are "lucky" because they are cute and people like the simple jokes. There's something to be said about that too, but they worked up that audience with consistency and giving people what they want.
So keep pushing out there, guys, always re-invent yourself, always try again, but get that quality as high as it can possibly go.
Then go higher.