As people have said already, weekends are dead times. Maybe try posting on like, Fridays and Mondays?
Also, I wasn't going to say anything, but argh it's bothering me so much i have to i can't keep it in
Your most recent comic, "Putting Safety First"... REALLY BIG MISSED OPPORTUNITY with the joke here. I mean the one you have is okay, but seeing as how the dad is delivering the line "You are so grounded" whilst Wade hangs from a tree? There was a dad joke in there you could have used. There was a perfectly good "No, I'm in the air, not on the ground!" type pun you could have made and you wasted it! WASTED IT LIKE THE OSMOND FAMILY WASTES WATER.
(I mostly jest).
But yeah. It'll take time to build your readership. Much like in anything else, there are a few comics now and then that explode in numbers right off the bat, but they're either a.) one of the very lucky few that struck a sweet spot, aka the one-hit wonders, or b.) they're coming to Tapastic with a fanbase built already through other places like their own websites, Tumblr, DA, etc.
Don't get discouraged if you haven't gotten 100 subscribers in a day. Focus on your work, don't overwork yourself, and most of all just have fun. If you're in it for the popularity and the fame, then webcomics is not the world you want to be in. Be in it for yourself and your enjoyment of making comics first and foremost, and your readership later when they finally come around.