This is going to sound like crap.
- Build a better comic
- Connect to your audience
- Fill your archive
Eagle
(Rinse and repeat)
One thing you should do that you didn't in your initial post is make your comic easy for people to find.
I noticed you didn't have any links to you work for me to click on. Don't be overly aggressive about it if it isn't the right place or time but don't make more work for people to find it. EX: in @shazzbaa's post she mentioned she when digging around the forums to find you work. Kudos to her for going the extra mile to help you (and then sharing the link for other readers) out but not everyone is going to be that motivated.
The best thing to do is just hyperlink the appropriate part of you comment so interested parties can click away and find your work. I always do this when I refer to my comic9 as an example. 
I'd say it's all about two words: persistence and consistence.
Don't get down when you're not immediately popular, and try to be consistent with your releases. That's probably the most important thing. After that, it's all about quality, and that will always be an ongoing assessment.
Best of luck, and much love.
LT
I'm gonna implement some of these strategies too of course. But I also wanted to suggest taking a moment to appreciate the subscribers you do have and the benefits of having a small number. I have 8 on my main comic so it's still feasible to keep up with their creations. Plus I can thank every one of them individually, and hopefully do fan art for their comics when I reach 10.
Hang in there. The audience for webcomics definitely takes time to build up. It took a couple of years for me but I heard after 6 months of consistent update you should see improvement.
My personal advice is to read and comment on series from other creators starting up. Feedback is always nice and usually goes both ways.
I even picked up at random "neighbor" comics in the fresh section and post a comment, say hello...
Also check this out for more infos:
I also have this issue, but I think I'm a little newer here than you are. I'm just commenting so I get notified when other people post on here because I would also like advice.
It's tough. I have a long history of shooting videos, so I thought a fun and unique way to promote my mega-rad comic, Satan Ninja 198X5, would be to shoot a live-action promo video. Since the comic is a sort of tribute to everything my girlfriend (the comic's artist/co-writer) and I love about the 1980s, we decided to make the video a series of mock '80s commercials, starring ourselves.
Even though the videos turned out totally awesome4, they haven't done much for us in the way of attracting new readers. But at least they were fun to make.
It seems especially hard to get noticed as a long-form comic. Gag strip comics can easily get attention on sites like Reddit, but I don't know of any good places to promote a long-form comic.
Unfortunately, just being good, isn't quite enough. Even a great, professional quality comic, like, say, Satan Ninja 198X, can really struggle to find readers. It's a cruel world.
ive read many forums that will help get subscribers. so far this day i got 6 subscribers. I think the project wonderful is effective most. here is the link http://forums.tapastic.com/t/free-self-promotion-through-project-wonderful/96233
http://tapastic.com/series/drawling-moment2
http://tapastic.com/series/dylpdx-the-sketchiness1
http://tapastic.com/series/Penniless2
http://tapastic.com/series/mechanical-district4
here's the ones i do, i hope you enjoy at least one of them,
dyl
No real way of getting more subscribers, still trying to find the answer myself. Relate-ability towards something that people already know (lore, re-told tales, mythic backgrounds etc) seem to start off well I've noticed. Original original stuff such as involving strange species, etc (if you're going longstory form) doesn't do very well since, well, how would readers look up something they've no idea exists/ or heard about?
You can try some really intensive networking, as in personally trying to talk to and get to know every community member out there and appearing in every comment section of every comic with an eye-catching avatar so people will click on you out of curiosity after seeing you everywhere. It's a very very slow process but it got me my first 100 or so when I was starting out.
You can also use groups such as Skype, online forums, Webcomic Underdogs or #Webcomicchat (weekends on twitter) as platforms for spreading your work outside of Tapastic, but again, in things like those simply shouting out your comic and link will probably not get you many followers, Sometimes people subscribe to you or follow you on other media just because they recall you were a friendly neighbor.
If you're out there for views and subscribers alone, ok... I'm not here to judge, feel free to take a look at some of the more successful or popular gag-a-day comics or whatever form you're looking at out there. They usually involve pop-culture references, parodies, fandoms, fetishes, whatever's grabbing the community at the time, and are often widespread on various social media sites (be sure to water mark your work somewhere where it can't be easily cropped off, I've had that happen to me once...) Personally such content gives me no joy creating it, but if you enjoy it and it just so happens to be something that the community your comic dips into is digging, you should be good to go. (Honestly look how many subscribers fan-comics of say Steven Universe Fnaf and Undertale get on tumblr... makes sense though because the story has already been widespread and acknowledged).
I feel the same... I have been consistent for one year and I have 29 subscribers, is sometimes a little disappointing when you let your soul on every page and letter, I got a full job and I try to make more than one page a week, I want to make more series but I am getting a hard time getting someone to help me, for the firs time I get behind my schedule and I am getting frustrated, but I´ll keep going, the best I can, and hope all the work and sacrifice worth it.
YOOOOOOOOOOOOOO i totally feel you like for Motsuro Project12 I have bene working on it for Years and have recently put it up on tapastic and the wait for subscribers i guess is kinda nauseating but you get what you get i guess.
I have 3 comics I work in one las year, updating every week, is a slices of life (Berenjenitos6), The other one, is a Western, I work in it rigth now (The Mexican3), and my new comic is a super hero, drama/comedy and is just begining (Disaster 53)
I am figthing whit the time to actualice all 3 whit my full time (nigth) job