I’m asking because there is a project now which badly needs subbers NOT in the States (license problems). But it’s no good for you.
To find open projects, go to fan channels which are still recruiting, not to dramas already airing, and offer your services.
However, on-air dramas need experienced subbers who can turn over the job quickly and efficiently, without the need of too much editing. Therefore, moderators are less likely to take a new person there.
As a start, I recommend looking for older dramas which are not finished subbing because probably most of the team left. Those are desperate for help. If you do help in a couple of these, your “CV” will look better, you won’t be a newbie anymore, and it’s more likely that you get an opening in a new drama.
My friend @mahoula has a list here on Discussions, with all the unfinished dramas needing help. I don’t know whether this list is being updated (look at the last one) but it may give you some ideas on where to look.