Complex Style

So I keep seeing icons that are gorgeous and they look so complicated, for example, the latest icons by kamilaa. She's not the only one, but she's the most recent example I have. There's so much going on in the icon and I'm having trouble effectively creating that style and also, icons with a texture around an image. It's like You can only see a little piece of the picture and the rest is covered by textures and brushes or maybe even other images. You know, like icons with multiple pictures?

I guess what I'd like are guidelines/tips for creating this kind of style. And if anyone has a tutorial, that would be lovely.

I can try to find better examples if you like. :)

Thanks.