How do you go about pinpointing where leads are falling off and how did you resolve it?
This is where analytics skills come in handy :)
To pinpoint where leads are falling off will largely depend on your go-to-market motion. The process will look very different from an SMB org, to a product-led growth org, to a sales org. That being said, you need a way to visualize the user path and understand counts and percentages along each step of the way to identify where the dropoff is occurring.
I’ve personally never seen a 'perfect way' to go about this. It is also so specific to your org that it’s not valuable to prescribe one set way to go about it. However, the crux of what information you need is still the common thread.
Once you have identified the root cause, you can then determine the remedy. Without understanding the root cause, though, you may be changing something that is working as expected. This should be an ongoing and evolving process. It does not have a finite start and stop.