"Cold Calling" off market properties

[Joshua Jackson]

I am currently searching for vacant properties to improve and have been investigating through public records to find properties that appear to be inherited or that have been owned for a long time and purchased at a low price initially that people may want to just get rid of.  I will be reaching out to them through letters or by phone (if I can find a phone number),  assuming I actually get a response, I want to come off to them as though I'm here to help them get rid of the burden and would like to have an arsenal of options based on their unique need. 

What are some creative acquisition strategies that I can use to keep the conversation going and stay minimal out of pocket? 

Are there any particular things that come to mind that I should say/do that would turn them off the conversation?

In others experience is this even worth the time and effort?