Welcome @IzzyStarr and @sarah-crows. It's nice to have both of you here. I've been here for a few months and am already seeing a decent readerbase, so I figured I'll share a few pointers:
1: The best thing you can do starting out is build a community. Joining in on the regular threads, talking genuinely with new creators, and just generally making friends. Some of my favorite creators are ones I became friends with first, and it opens the way for a lot of mutual support.
2: Speaking of mutual support, you may be tempted to try sub 4 sub threads. There's a constant debate about these types of threads on the forums that just sort of repeats itself every few weeks, but my advice would be to look for and create Read 4 Read threads instead. You'll get people actually reading your stories and comics and those who sub will genuinely come back to read more.
3: You want to have a consistent schedule, and a good buffer to prevent burnout. It can be tempting to drop a lot of content at once and watch the numbers go up, but its far better in the long run to work with consistency and reserve. Think of the tortoise and the hare here.
4: Be sure to put a link to your story on your forum profile. If you click my name you'll see a link to my series. You'll get a lot more clicks just doing that and engaging with people than you will dropping your link in threads where everyone else is link-dropping.
I have more but don't want to overload you all, but those are definitely the big musts for promotion.