Even with the readings listed by my lobbying-focused post-grad course, it has been difficult finding anything that actually explicitly outlines how to do it. Despite being somewhat dated in its specifics about the digital realm, everything here is still completely relevant and applicable to 2020.
Extremely UK and EU focused, with a large section on the US, the later sections of the book, many other jurisdictions are explored and explained in reasonable detail.
The first section of this book is invaluable to anyone that wants to know how to engage in political lobbying.