As the proud owner of a channel
with almost 500 subs, the biggest tip I can give you is to keep in touch with the people in the comments. People always like it when the guy that made the video answers their questions.
Ofcourse, editing also comes into play, and coming up with interesting or comedic gameplay. Another tip for every CS:GO player out there: The more competitively you are at the game, the more depressing you'll be. Don't take the game too seriously.
A great example of a good CS:GO Youtuber is
Teo. He and his friends make funny CS:GO video's where you can see that they don't take the game too seriously. Learn from them.
Next is advertising. Kinda like this:
[ Shameless Self-Advertisement ]
aka just keep bugging people to check out your video's. If it doesn't work after 5 times, they most likely aren't interested in what you make.
Also, don't get copyright striked.