I use indirect methods for promoting my comic. There's no right or wrong way imo (though that can be debatable).
Indirect promoting is basically becoming a part of communities and letting your actions help promote your comic. What I mean by that is, I don't post a link to my comic unless specifically asked or if it's ok to freely do the like on social media accounts. Instead, I offer up my advice and experience, I participate in collabs, guest comics, community activities, and let my reputation play a bigger role than spamming my link.
There's also a lot of advice about promoting through social media and each site has a different set of standards that'll make you posts more appealing. Tumblr, for example, it's easier to gain traction there by posting fan art, WIPs, Art tuts, and blogs.
And then there's ad spaces like Project Wonderful, which I've obviously have found super useful.