How to approach homeowner?

[Jed Reisner]

I've been reading about wholesaling properties and I'd like to try.  I've spotted at house in my neighborhood that is run down and overgrown.  It also has an empty lot next to it that appears to be part of the property.  It's a very dense and desired neighborhood. I can't tell who lives there if anyone, but, I've occasionally seen a car and I suspect an old guy. 

How would I approach someone like this and see if they would consider selling?  There's no reason to think they would, but, it looks like a very valuable lot to me that isn't being used well.