Since I only meet 1/3 of that requirement, I figured the internet was the way to go.
Vex did fairly well. We had a decent-sized audience that interacted somewhat regularly. Deputy Witch started going up before Vex ended, so we were able to benefit from some crossover readership. So what I learn from Vex?
THE MESSAGE AND THE MEDIUM
There are exceptions to this, but let's think about the medium for second. Daily updates of a webcomic are somewhat reminiscent of the comics page in the newspaper in that 1) they're going to be ready quickly and 2) they generally have a punchline to every strip. There are exceptions to #2 obviously. Judge Parker, Mark Trail, Apartment 3G have been going on for decades and have an over-arching story, but most people who pick up the comic page typically go for the gag strips that have a complete thought. They set up the joke and then deliver. The reader puts the paper down and then goes to work.
That ryhythm of setting up the punchline, delivering, and ending gives a sense of closure that fits the medium (i.e. the paper) and translates well to webcomics. Years ago I did a comic like that and we built up a readership fairly quickly. Vex was written as a graphic novel with three acts. The pages weren't written to be read one day at a time, rather they were designed to serve the overall pacing of the book. Reading it online meant that there was a slight requirement of delaying gratification on the part of the reader. You had to stick with it for the payoff (punchline) that each page was building towards.
No one is going to spread page 25 of chapter 4 around the web (giving you free advertising) like they would with a clever PvP or Penny Arcade strip. So, there are challenges inherent in promoting a larger work online as opposed to an ongoing strip designed specifically for the web. Not that it can't be done, but it takes time.
IF YOU BUILD IT THEY... MIGHT COME.
Unless your comic is Axe Cop (which 99.999% of all comics aren't) you're going to have to build up an audience slowly over time. Right about the time that Vex was starting to get a several hundred readers a day....Act III hit. And then, soon after, came a page with the words "The End."
It took a year and a half to run through the whole story, 146 pages, and then...no more updates. I've heard some successful webcomic artists say to expect no one to read your comic for the first six years. That might be hyperbole, but it definitely takes more than a year and a half to build a decent audience. Again, unless you're Axe Cop. Which all but one of us are not.
But let's say you have a few hundred people reading your comic every time it updates. How could you whizz that extremely modest readership right down your leg?
GO ON HIATUS
When Deputy Witch went up we had a decent readership right off the start because of Vex. (Decent for us anyway.) In the summer of 2011, a variety of things happened and we put the book on hiatus for a couple months. Then those couple months turned into almost four.
If you learn only one thing from all I've said, learn this:
Never, Never, ever, ever, ever go on hiatus. Never! Do you hear me? NEVER!
Why? Because you'll 1) make people angry 2) lose readers you probably won't get back. I looked over our Google Analytics, comparing our readership today vs a year ago and during our hiatus we lost two thirds of our regular readers. Now it's true, making comics is time consuming and exhausting. And it's true that the internet in general can be a cruel, cold place where all your efforts are consumed by faceless persons who give little or no feedback. But those faceless persons are, well, persons, and they do enjoy your work or they wouldn't keep coming back. It is hard to remember that when the comments section is quiet and it seems like there's no organic buzz going around about your project. But everytime you have a regular reader, that's a postive thing. Don't lose them.
And the quickest and surest way to lose them is to stop posting. I know, life happens, and if this isn't your job (which, it's probably not) there will be times when you'll have to put things off a day or two. Maybe a week. But for crying out loud, four months? I have no idea what we were thinking. Live, learn, and don't make the same mistake twice.
If you want to build a successful webcomic... we'll I don't really know what to tell you. Go ask Scott Kurtz or Ethan Nicholle. But I know a few ways how not to make a successful one, and like they say: "Write what you know."