Any Guide/TUT Available To Designing Good Icons? topic

Hi,
I was surfing and found some Good Icon Packs By Great Developers. They have designed icons awesomely. As a Beginner, I have One request to them to Make One Guide On Designing Good Icons. In which they should cover Basics and Advance concepts. I have seen many guides to make icons pack for different Launchers like NOVA, GO,APEX,AWD etc. I hope you are understanding what I want to say. So, Its my humble Request For Icons Designers to Make 1 guide For Designing Icons.

Thanks