When I meet someone new who could be a potential client whether it be residential or investor should i be adding them to a certain group in my phone as well? 

Please send your email/phone if you or someone you know might be interested, thanks. 

My method is to message (text, phone, email etc.) landlords who have posted to local classified sites looking for tenants, and ask if they would consider selling their rental property.

Sounds like $470K is not a huge discount (if one at all depending on how much it would cost to fix it up so it could even sell for retail).2) Tenant screening is extremely important.

How do you find out the owner and phone number of an empty lot without paying some website?

While you are examining heating, plumbing, electrical, smoke/CO detectors, weatherization, locks/doors/windows/screens, appliance function, etc, keep an eye out for lease violations and how well they take care of the unit.

I would contact the directly by mail, phone or knock.If this intimidates you, then you are not ready. 

However, I'm concerned that (1) homeowners will perceive me as a self-interested investor and (2) when I get them on the phone, they will only want to know my buying price, not allowing me to build a relationship.B.

If you have an Android phone, I use BeyondPod to listen.

If you choose to go that route make sure there eviction rate is low because they are screening the tenants.