Alex Hormozi is a master for creating funnels, and he has a knack for describing the process in an easy to understand way.
His book breaks down each of the components of a multi-touch marketing campaign, and makes you realize that you have leads from the get go: “your phone has a bunch of contacts”. I haven't bothered to clean mine and have brought over numbers since the year 2000. I have thousands of numbers.
You know what they say, “nothing happens until something is sold”.
Alex Hormozi, $100M Leads: How to get strangers to want to buy your stuff.
I just listened to a few summaries of his books which our library has.