Poke Radar?

[AdventureSerum]

Can someone tell me how to use the Poke Radar properly? I must be doing something wrong. I hear loads of people talking about getting up to thirty of the same Pokemon in a row, but no matter what I do the most in a row I seem to be able to manage is about eight or nine, and that's when I'm really lucky. Is there a difference in the amount of shaking that happens in the grass? It looks like rarer Pokemon are in the grass that shakes more, but I don't have any proof.

[Phoenixsong]

Here you go.

How the radar works, complete with tips for shiny-hunting. It's hard, but it works.