If you're talking Youtube, it's all about click through rate. In other words, the algorithm shows the video in a couple of peoples feed, and if they click on it, the algorithm show it to a few more people, and that keeps going. But when it doesn't, it means not enough people click on the video.
2 easy ways to fix it are: better thumbnails, and better title for the vid. Thumbnails lure peoples attention, titles lure interest. I believe you can track how many people actually click the video now, so make a couple of thumbnails and titles and switch them after an hour or so, this way you can find out what titles and thumbnails work the best and build from there (but don't get too clickbaity with it).
Of course, when people click, they want to see a good vid, so keep them interested for at least 8-9 minutes, I believe that's the threshold where the algorithm thinks the video is well liked. And getting likes and subs is always good.
I'm not a Youtuber, so I haven't tried these things out in practice, but these were some tips I read online.
