What you can do is have social media accounts, like a facebook page, instagram and twitter.
In each social media, put the link to your series, a promotional image of the series or chapter, then use the hashtags of the platform you're using to host your series.
Then, of course, be active in the webcomic communities, be it facebook groups, discord servers, the tapas forum and such. Obviously, I would recommend to have your series on both platforms if possible try to publish your series on the platforms of the communities you're in, if you're in the Tapas Forum or Discord try to promote your series using the Tapas version of your comic, since it's in part a rule and a way to fluctuate the engagement of the community in the platform. Same thing happens with Webtoon.
You can participate on the "Post your latest chapter" or "Promote your series" kind of posts in the forum or even in Twitter threads. Sometimes just dropping the link or other times providing a small summary of your series.
Some authors promote themselves on TikTok, Youtube and Twitch by showing their creative process, be it live-drawing some panels of the webcomic or recording and then making a time-lapse of it.