YouTube is a computer program. It's just a robot - a mathematical algorithm that looks at how engaging content is and promotes the more engaging content over the less engaging content. The only way to consistently be successful on YouTube is to produce great content. Someone might get "lucky" in the sense that they happen to film some great content but the algorithm can not be fooled or tricked and it does not play favorites. It has nothing to do with luck. It's just math. Attempting to fool or trick the algorithm will lower your score and make it less likely to promote you. Make good content and write accurate descriptions and tags. That's all you have to do. The algorithm re-calibrates every 24 hours and does a major recalibration every 30 days so even if you get "lucky" by getting a shoutout or something you will be getting almost zero residual traffic from that shout out after 30 days if your video is less engaging than other videos with similar content. That's why it's a total waste of time to promote your videos. Make great content so the algorithm promotes it for you. If you look at a video that's got great content in a popular category like gaming it can get 30-50 thousand views a day. None of it from subs, none of it from "social media". All of it from the YouTube robot suggesting it to people and displaying it in search. "Social Media" accounts for less than 10% of the YouTube weighted scorecard (the type of algorithm they use). Unless you get over 100 facebook shares, tweets, ect - the algorithm doesn't even take it into account.
The only thing the algorithm really cares about is audience retention. Over simplifying the explanation to illustrate a point - if I make a sixty second video on "How to cook a rabbit" and the average person watches it for 49 seconds and you make a sixty second video on "How to cook a rabbit" and the average person watches it for 50 seconds YouTube will promote your video over mine every time. You'll end up with millions of views and I'll end up with none. You've got to focus on audience retention. I look at my "relative audience retention" in analytics every day. You have to see that chart above the average line they show. If you do that wether a video is 10 seconds long or 10 hours long, wether it's on a popular video game or a local news story, YouTube will always be promoting it over other videos that are below average audience retention.