DEFINITELY the best is having an online presence.
Use Twitter: regularly talk about your art, post about your next update like a pic of your sketches, talk about how you ate a burrito because life fucking sucks, and post your link whenever you update your comic. Follow other authors too and interact with them regularly so you become present in the community.
Use Reddit: Go to the Comics subreddit and post your updates there regularly! Don't forget to post your links! Be sure to support other artists too, be a part of the community, and just become very EPIIIIIIC! Make sure to check other subreddits too!
Use a website: Make a domain for your comic and post all your work there, preferably earlier than when you do on Tapas and Webtoon.
Use the Tapas forums: interacting with the Tapas community and helping your peers is THE BEST way of getting readers who might be interested in your work! Read them, make them your fan, and become their fan as well! It's like sub for sub but instead of dead readers, you're actually building a healthy friendship and communication with your peers.
INSTAGRAAAAAM! THE BEST WAY TO PROMOTE A COMIC! Post that comic update, use a fuckton of hashtags, and follow a lot of artists! Become an active member of the community and maybe even pay to make your IG post an ad! I haven't tried it personally, but I heard it works!
There's so many other methods too out there and the best way for you to find your readers is get comfortable with at least 1 to 2 social media site ONLY so you'll have your full attention on those places! Hope this helps!~~~ read my book UwU jkjkjkjkjkjkjk! ...unless.