I've been on both for 6 months and still haven't gotten any followers or likes on my posts. Does anyone here have any experience of this?
As someone who used to have a little over 10k followers on one of those platforms, I'm going to firmly request you to not even try. I've long since deleted either of the accounts; it was a mistake for me and could be for you.
More if you are a minor. Both platforms are the worst when it comes to the kind of people you are going to meet—the experience isn't worth the effort, in my opinion.
That said, if you are still so inclined, the first step is to mass-follow people. Find a creator who posts similar content to you and follow their followers. Unfollow those that didn't follow back, rinse, and repeat. Your new account needs a follower boost before the algorithm decides to push your tweets or posts. Don't do it fast enough to be flagged, though.
The next step is simply to be active and engage. Post tweets, reply, like, whatever there is for you to do. Find a schedule to post on Instagram, but don't post something completely random. Use hashtags extensively. I'm assuming the new meta (pun not intended) has shifted towards reels, so that's something you have to do as well.
Once you have a comfortable follower base, you need to find creators of similar reach. Do shout-outs and maybe collaborate with each other. You are also likely to be added to a number of groups by then. Be sure to be active and stay on good terms with people. They are going to be the ones who share your stuff around.
The last step is to realize you wasted yourself, and none of your followers matter. People don't care. And if you are a minor like I was and even have a tiny bit of similar experience to mine, you've accomplished your goal. Tons of likes, DMs, and message requests. There may be a few scam messages, NSFW, and harassment mixed in. There may even be your real name, address, photo, and phone number, who knows?