Ok, so everyone else's respond Is right on track but I will deviate from your typical response and I will use my 2 years of youtube experience so far.Keep in mind you have to take any advice with a grain of sand or w/e the saying goes.
In order to be successful in you tube, there are a few pipelines to follow.
You must have something unique, something that you invented/created/born with.(examples: Markaplier has his voice/charisma, Jacksepticeye has his accent and hyper/loud charisma, angry joe has his parody reviews with his own characters (Corporate commander) and so on. Notice how all of them have something rather unique to them that they either created or are born with.
All of them at some point had that one or few videos that made them famous or known, once you establish your presence you are set.Notice how gradeAunderA was nobody until his started making videos about drama/picking up fights with other youtubers, he went the drama route or the conflict pipeline. Others like pewdiepie simply were the first with the idea and that made them famous, others work there way up from 0 subs, year after year grinding it until they were known by the masses. While others become famous by simply following video trends, like when Keemstar was being "exposed" everyone jumps in the bandwagons and start adding there opinion in to get them clicks. Leafy was nobody until he starting being a douche to everyone on the internet, and that feeds the trolls and the trolls love it.
You need to find your thing, your umphh that makes you who you are, the reason why your friends like you and put it out there. If you have a voice, use it! if you are loud, be LOUD! YOU have to stand out.If you are weird or like making people cringe, then go full weird mode.You want to be the biggest c**t on youtube? by all means cuntitout, but be prepare to face some heavy infamy but people have short term memories and this on the long run turns into fame/success.
Most of us in this website like to take the normal route, the good guy route, but this one takes time and by time I mean years of uploading videos until people start noticing you.Take me for example, I love games, I love doing reviews, I have taken inspiration from angry joe reviews and have done my own only to get called a cheap copy of him and yet ironically is my best review video view wise. One day my gf was tickling the hell out of me and I started laughing like elmo, she told me "why do you sound like elmo when you laugh?" I never knew this about me..and so EvilElmo came to exists. I have to admit doing his voice hurts but behind the scenes I cant stop laughing at my own jokes, not to mention the countless hours I annoy her with the voice.
This is not to discourage you, but to make you look deep inside and show us all here at the internet...who is ryan?