I'm still in my first years so no data to compare really and as my channel is growing I don't think I'd be able to tell. I know some of my videos are less popular with the younger viewers (don't think they are into castles as much as I am lol) but other videos have done really well.
Get your cat on your bike while vloging and you're onto a winner
Seriously, if it isn't scared to death, it would be really funny to record peoples reactions to seeing that.
Of course you'll get a lot of hate for endangering it...
I have seen so many channels that are just stealing stuff off other people and getting more subs than you could ever hope for as a motovlogger.
Because they know how to work the system and maintain interest.
Titles, thumbnails, tags - these are important.
Youtube is basically a rather clever search engine.
This is an interesting site which lets you see roughly what can be earned from uploading stuff that gets a lot of views.
http://socialblade.com/
Totally hipAttracting the younger viewers seems to be a challenge for me too. I mean, come on, I am a hip cat that knows about the niftiest trends right? Right?