ok Haven't succeeded in marketing but from people who have here's what they do.
1. post in everything you can get your hands on, Youtube, Twitter, Instagram, Forums, etc. this is the easy part now for the hard part, what do you promote?
2.Promote your art progress, from what I can see from the biggest winners in promoting their work they only promote their art pages 0 dialog and all art or sketches (I'm stuck on this right now cause I am writing instead of drawing ='C).
3.Show your opinions on comics and your making philosophy, these days just being a name on a page ain't gonna fly, you have to be charismatic too (I know I hate it too) so try talking about the comic and what is/was your approach when making it.People like this and creates a conversation around your comic.
again this isn't written in stone it's just some trends I have seen going around the comic space and what has work and what hasn't.
Extra. Always remember to thank people who support you from time to time =)