You might be using the definition of "broker" differently than us in this case (perhaps you're talking about the managing broker in the firm, not simply an agent), but even then, there shouldn't be any reason for a broker, if wholesaling, to have to list a property. 

Simply put tell everyone you know what you are doing and the returns they can expect for X amount of investment dollars and ask them if they know anyone interested.

Should the first attempt at contact be a letter, knocking on the door, a phone call?  

As opposed to simply defaulting, which is a bad sign.  

There is a few steps involved and there are literally books written on these subjects so I am not going to even attempt to tell you what all needs to be done.

It is currently vacant while I am renovating it and I am still trying to decide if I will attempt to resell it first or hold it as a rental. 

The house is paid off but the owner/builder is in a nursing home. l am attempting to fix and flip but would like to offer more than one option for the seller.

If it doesn't work out simply walk away.

Of course you'll simply be memorizing, and not learning.

Our goal is to always start out attempting to buy for the lowest price possible price and adapt the buying strategy if needed.