Well the first thing about promoting, is don't. Not yet at least, yeah tell your friends and everyone, but wait to do any real promotion until you have a few pages (I've see it recommended as waiting until you have up to 20). Basically if your sending people to your comic and you only have one or two pages up they're going to read and forget about it, you want to make sure that you have enough for readers to get invested so they want to come back for more.
Once you're there, your best (free) promotion tool is going to be social media, Instagram, Tumblr, Facebook, Deviantart, Reddit, basically you just want to keep putting things out in front of as many people as you can. If you already have a following on social media, you pretty much have a built-in audience. There's a bit more subtlety to it, but basically just don't be annoying with it.
Also, I would advise against using that brushy typeface for anything other than titles.
Oh wait, I guess I have extra advice: remember that a comic is not just pictures with words on them. The lettering needs to be part of the composition. You seem to be pretty good with that, but it's one of the most common problems I see, so I figured I'd mention it.