The thing is, there are hundred of thousands of people doing the same. Getting noticed is extremely hard. You have to propose something original and different which makes you pop out from the others. Also, don't re-post videos from others. You need to create original content, enough to get attention. Also, to get attention, you need to promote your channel, on social networks, and things like that, building a network of friends, who can help spread the words about your videos. And if your videos are interesting enough, people watching will share them, and so on.
Be different, show something unique. Don't be like everyone else.
Know your audience. What is funny in one part of the world is probably not funny in a different part of the world.
Play to local markets first, then try global.
Throw some money at the project (get a movie star or singer for a video, ain't cheap). Newspaper, TV, Radio ads. And do the social media, too.
Hire lawyers, because if you DO come up with something unique every tom dick and harry out there will copy it and run it into the ground unless you protect your intellectual property.
If starting from scratch be prepared for a year or more just to get noticed, and a year or more after that to get any kind of growth.
The only thing that bypasses all the above is having that one amazing viral video, having it FIRST, and then being able to immediately followup. It's that last part that is near impossible.
Above all, if this is something you really want to do, be dedicated, keep after it, and have a day job to cover rent and eats. There are rewards for doing something of value, even if only for yourself.