rethinkyoyo.com has some pretty advanced stuff…
Just search for the trick name on YouTube and find a tutorial you like. Assuming you’re after known tricks, if not just look around, a lack of tutorials isn’t an issue any yoyoer will have these days, i have a playlist of 75 or so tutorials on YT right now that i plan to learn… http://www.youtube.com/playlist?list=PL9B-smeRReJYLkDxenJ9Zd1e5Xd34UVxL They range from easy to god-level, and from so-so quality to really well done, click through and i’m sure you’ll find something you like, and if not the channels they’re all from are all great ones that you can have a look around.
If you know what the trick looks like and you know all the methods people always tell you to use, listen to this: Practice and you will get it.