I've been thinking a lot about this lately (and by lately I mean the past couple years lol).
Two of the most successful web serial authors you'll find on WFG are Drew Hayes and Wildbow. In this post I'll be addressing the sort of success they've seen. RoyalRoad and the LitRPG scene is a different beast, so if you want fast success, I'd recommend talking to some of the guys who came from that community (a number of them are on here, so I'd be surprised if they didn't chime in.)
So, Wildbow and Hayes. Thinking about their writing styles and business models, they have more differences than they do similarities: one's dark, the other more humorous; one has focused exclusively on Paypal/Patreon, the other has found success via Amazon. On and on, though there are some obvious similarities -- they're both youngish (in their 20s or 30s) white guys who wrote superhero fics and posted them online -- I think their styles and business models are different enough to highlight the similarities that are important if you want to run a successful web serial.
The first similarity that jumps out at me: neither went into this planning for fiscal success. Wildbow did it to improve his writing. If memory serves, Hayes did it for fun? They both committed to telling loooooooong stories, with no promise of reward. Now, you'll notice: that's a shitty deal. You're pouring your heart and soul into something that will literally take years to finish, something you can't take a week off from (for reasons I'll get to in a sec).
I'm sure some of my more virtuous colleagues will have good takes on it. "No one asked you to write this so they're doing you a favor by reading," "there's already a glut of people out there writing things for other people to read, so the market isn't going to reward you easily for your writing," etc. etc. You want to know the truth? Fuck that. You're doing something awesome and something valuable, something readers will derive enjoyment and wisdom from after awhile. Unfortunately you won't get paid for it for a long time, because as it stands the marketplace is designed to fuck writers and devalue the written word (there are actually a # of advantages that come from devaluing the written word and I'm not 100% against it, even tho it angers me that writers get fucked over as a result. But that's a separate post and this one's surely going to be too long anyway. Plus it's hard to write all this shit on an iPad. Christ.)
That said, the truth is pretty unescapable. Most successful web serialist spend years before finding true success. So you have to figure out something that attracts you to web serials other than potential money or fan base. Maybe a love of the art form, or for the story you're telling. Something in the world you're creating that makes you think, "I want to spend years here."
The second thing Wildbow and Hayes had in common was genre. Though both of them branched into other genres later, they started with superheroes. This is important because when they started, superheroes were an underserved market. People wanted to read about supeheroes. So among the smallish group of people who knew about web serials, a largeish percentage of them looked for superhero stuff. But Hayes and Wildbow wrote their tales during the early part of the boom, which meant there were way more readers than there were writers.
This is a semi-difficult topic that I haven't fully mastered yet. Chris Fox wrote a great book about it for the Kindle market called WRITING TO MARKET. I'd say a number of his insights/suggestions are transferable to the web serial world.
The third thing? Consistency. It's not complicated, but it is hard. You want to write regular posts, proabably at least 2 times a week to keep reader interest, w/ a minimum of 800 words per chapter (at least) to avoid annoying readers or having them forget you. At the same time, you have to be able to keep this schedule during the busiest week you have in the next two or three years. Simple to explain, difficult as hell to actually do.
So those are the pieces of advice I would provide someone starting out. The second point doesn't work for you specifically since you already have your genre, but that's alright. The grenre thing is probably my most controversial point anyway.
When it comes to getting eyeballs on your work, I would focus on getting the WFG listing and maybe cross-posting some of your serial to RoyalRoad. It can also be nice to start a TVTropes page for your serial. Other than that? I would mainly caution against "the feeling that I must really be doing something." Your main goal is to write and keep writing. Make sure you can manage your schedule, think as much as you can about your world and its characters.
Thinking too hard about stuff outside the serial will burn you out. So focus on the serial. Let it become a part of your life. Maybe your serial is the bonsai tree that grows and flourishes around your life, or maybe it just becomes a fun hobby you nonetheless commit to.
Either way, find a good genre and be consistent in the long run. Once you've figured out how to do that?
You'll be golden.