There is a pinned post about it on this forum.
But if you want bonus tips, maybe it can be a good one:
so, the main problem with social media is, it is really hard to reach those people who are not creators themselves, because non-creators rarely reach out for certain hashtags like "webcomic". They are mostly in their little world, and bother with their own hobby. Sooo my advice is you should find that topic what is most connected to your story. It can be a hobby or an object what has groups(for example in facebook), fanbase etc. and advertise for them. But don't violate that group's rules! It is important. And don't be too explicit.
So for example if your comic contains lot of mountain climbing, apply for a mountain climber group, and try to make a relevant post.
Otherwise I'm really bad at self-promotion. I always feel I should not tell it anyone about my comic because they might be not interested and I just annoy them... I hate bothering people.