Hard work and dedication. There are no short cuts for most people. Set a goal like 40 new videos before the summer and try to make each video better than the previous one. Storytelling, camera work, video quality, audio quality etc. Work on improving your audience retention. Each new video is a new way for people to find your channel and as your videos improve more and more people will subscribe and watch more of your content. But you need to look at it as a marathon, not a sprint. Expect it to take years and be grateful if it goes faster.
MrBeast started uploading in early 2012 he didn't get his first viral video until 2017, that's five years of him working hard, improving, studding YouTube and creating hundreds of videos.