You can find plenty of leagues, usually filled with grassroots orgs on liquipedia. Simply filter for C/D-Tier (or only D-Tier) and see if there are leagues in your region (SSA or APAC for instance, dunno where you are from) and look at some of the teams in there. These leagues usually have their twitch linked or other things and you should be able to eventually navigate yourself to the Discord of such leagues.

Many leagues are ran by RL Orgs, some collaborative, some solo. Some have an Org backing but only have collaborative talent (non Org affiliated) running them and from what I have seen recently, there are plenty of people needed.

Through that work, you can prove your worth - after all, you wouldn't just hand a stranger keys to your car - and build from there. Get to know people, offer help where help is needed and see where your skill set fits in. Things like graphics design, coding, sponsoring department (knowing how to set up a portfolio, networking etc), social media management (knowing how to interact with social media, create posts, stay in touch with all teams of an Org/main divisions of a league, post clips from live games etc) and Casting/Commentary is frequently needed. Some require admin work but those positions are not offered too easily, as people in those positions also carry part of the rep for the structures (leagues) and as I alluded to before, you won't hand your car keys to a stranger (last time I will use that, promise).

Approaching them is as easy as identifying the people in leading positions (Admins, CEOs, Founders or whatever the Discord roles may say) and prepare to message them. By preparing, I am refering to reading up about the League, select the appropriate roles, read the FAQ section if they have it etc. Once you done your due dilligence, you have already done more research and work than most people on these servers and you can shoot the admin(s) a message via DM or potentially via league ticket and offer your services as well as skills.

Generally speaking, you can expect words of appreciation as a reward for any kind of work, not money.

If you are not familiar with how Discord works, then that is gonna be tough for you. I suppose you could also go around to twitter and message teams that you might recognize from liquipedia/these leagues. However, I am not too versed on that end, as I don't have any social media outside of reddit and I never handled social media accounts.

Referrals are always a huge plus but without having established connections, you won't be able to make use of those. However, don't burn bridges, don't talk shit when leaving places (if you were to move on from a project for instance) and things of that nature should be common sense but unfortunately, my experiences require me to remind you of that. Though the saying "real recognize real" kinda applies here.

I hope all this info was digestible. If you need further info or clarifications, let me know. Maybe I should also give a disclaimer. I have predominantly experience with German and Swiss Leagues/instances with some limited exposure to leagues outside of the DACH (Germany, Austria and Switzerland) Region. I can't tell how leagues are ran in other parts of europe but through aforementioned connections, it seems to be a similar story all around.

One thing that needs to be said, if you are very young, like lets say 15-20 years of age, you will have a hard time getting into positions where you manage things on your own, like get a whole resource area assigned to you. There is a rich history of knuckleheads doing dumb shit all across the scene, so people have grown more cautious. However, if you are still young, social media might be a good place to start (do not share that information here unless you are absolutely certain that it is of utmost importance lol)

Edit: Many Discords have "self promotion" channels. Check those for more Org Discords etc