Creating a list of mailers/cold calls

[Gage Green]

For those of you who go out driving around looking for properties and are creating lists for cold calls/mailers. Other than visuals what are some of your “criteria” how do you decide if its worth sending out a card or making a phone call to? I ask because this past weekend my wife and i found about 20 properties that from the outside looked like the could be quick flips or good rentals with some work put into them. And I’m not sure if I should be sending mailers to every single one or if i should be trying to weed out some of the properties before I send out/make mailers. Maybe I’m over thinking things but i am just trying to be as efficient as I can and make the best choices i possibly can. Thank you in advance for your time and input!