Best Product on Product Creation for Funnels?

Hello
I want a product on product design for when using funnel marketing structures.

I do not want a product that outlines the structure of the funnel.
I think I understand that.

What I want is more how to design the COMPONENTS of the funnel.

For example, I realize a free report should always come first, then a low-barrier entry product, then upsells, etc. And email followups for each, etc. So I understand a funnel sequence.

But what I am wondering is

What makes the best freebie? I realize it a hot piece of information that they are dying for, but what is the best way to come up with this idea? Should we pre-sell the main product in this area or not?

What makes the best product?

What are the best types of upsells?

Should you write the main product first and then pull out pieces for the free-offer and the upsells?

What makes the best content for followup emails?

Etc. etc.


Does anyone know of any products that explain this very well?

I hope I have explained this well. Its late.

Thanks a ton