Proper venues like clubs and bars will almost certainly have their own sound system. Likewise, if there’s a one-time event outdoors or something, the organizer will generally be responsible for this. Sound system stuff is usually only your responsibility if it’s an event you’re organizing yourself.
However, you should probably bring your own mixer so that you only need a pair of stereo cables to hook in to the house mixer. Check with the organizers if your output needs to be RCA or 1/4" (or just bring both) and how long your output cables need to be. Bring your own power strip to plug everything in, and again, check with the organizer to see if you need to bring an extension cord.
If there are events or clubs in your area that play music similar to yours, go to them. Find out who the organizers or DJs/artists are and talk to them (when they’re not busy of course). Record some live sets on your own and upload them to SoundCloud or some other platform so you can send the links to event organizers as an example of your work. Organizers are unlikely to book you if they don’t know what your live sets sound like, because it’s a bit of a gamble if they don’t know that your music matches the vibe of the event.
If you’re shy and introverted, approaching strangers like that might feel intimidating; it definitely was and still is for me. At the very least, you should still try to go to events to get a feel for what they’re like, and maybe try messaging organizers and artists on social media to ask them how to get involved. Or if you have any friends who are already involved in the scene, ask them.
The event organizers will give you a time slot and probably ask you how long of a set you’re comfortable with playing. I think a one-hour set is a good target to get comfortable with, but really you need to be making live sets on your own and practicing them. If you only have enough material for 30 minutes, that’s totally fine, but you need to have a good idea of what duration you’re comfortable with/capable of.
Definitely don’t use alcohol as a crutch to overcome that feeling. I have pretty bad anxiety, so I totally understand where you’re coming from. Serious event organizers probably won’t be thrilled if they find out you’re getting drunk as a coping mechanism (although if it’s a college town and they’re all students they probably won’t give a shit because… college, but it’s still not a good idea).
Practice. Make live sets and practice them multiple times. Have a plan, know what you’re going to do. Make notes of what you think works and what doesn’t, and then iterate on that until you’re satisfied with it. You should be doing this even if you aren’t nervous about playing.
If you’ve recorded a live set or two, sent them to event organizers and they book you, it’s because they think your music is good enough for their event. Trust their trust in you. Have some confidence in your own music. You can’t completely get rid of that anxious feeling, but confidence and trust in yourself go a long way. Alcohol is only a temporary crutch that will increase the likelihood of you making mistakes while playing live. There’s nothing wrong with drinking, but absolutely don’t use it as a coping mechanism.
Of course not. Opportunities to play live sets are much less common than opportunities to DJ, so it can be hard to find them. It can be frustrating if you feel stuck. But if you truly enjoy making music, you should do it even if no one else will hear it. I’ve been trying to find opportunities to play live sets since early 2020 (obviously the pandemic didn’t help) and only played my first gig this past summer. But after playing that first gig, getting to know other artists, DJs, and organizers became so much easier, and I’ve now played three times in the past six months. It felt insanely difficult to find that first gig, because it’s a risk for event organizers to book someone who’s unproven, but after that, other organizers could see that I had already done this before and the people I played with could vouch for me, so it felt like they were less apprehensive to book me.
Above all, you should be making and playing music for fun, for yourself. You can have confidence and believe your music is good without being arrogant. Don’t worry about social media, play counts/streams, or an apparent lack of opportunities to play live, none of that shit is indicative of the quality of your music. You can always improve if you enjoy doing it.