I am interested to know what techniques are used to locate homeowners and investors who are willing to do owner financing or hard money lending.

Remember you can always build upon that as you go through to the next property or tailor it down. 

Even if you do not plan on doing wholesaling and flipping, consider learning how they operate and apply those same techniques to your buy and hold acquisitions.

Thanks Vincent,Big Fan of the BRRRR technique.

-How does your cold calling compare to other lead-generation techniques in terms of conversion rate and return (on time invested)?

We put out a quality newsletter and used inbound marketing techniques learned from Hupspot's "Inbound Marketing" book.

I will know soon how this technique works under extremely difficult situations.

my technique is to look for a bad roof, go to the assessor's website and find the owner

Mastery is not a real estate technique but a very strong network of active investors surrounded by very successful minds in the business of building a business that is sustainable for the long term.

Do you know of any resources like BiggerPockets but more tailored for Germany?