Some people just want fame and money and millions of views out of their channel. I generally avoid looking at channels that I see posted all over pewdiepie/zoella/PointlessBlog and all the rest of the top selling youtubers.. If I see their name spouting 'I AMEK VIDEOS 2

CHECK ME OUT!!!' on 35 different videos then there is a 90% chance I will not even look at their channel...
But, as much as I hate this kind of thing.. I sometimes subtly advertise my channel;p In terms of..
If someone posts a video about something, I'll bring up maybe one of my videos that talks about it too, but not in an obnoxious way like 'Omg I did a video about this too!! (check it out)"
Not entirely sure how to word it haha..
Anyway.. I think advertising yourself in non obnoxious ways can be good, but don't go around a tonne of small channels asking for them to subscribe... I dont know about you but I hate that sh**..!
I don't advertise my channel pretty much at all. I think making a name for yourself on other social media is also a veryyy good idea, like twitter and tumblr, those kind of places...!
I think it is possible to get to the top places if you don't wh*r* yourself out, it can just take a bit longer..
not sure if this is any help lmao..