Where you are not insulting their intelligence, but you're also making it clear that you are sitting there with the intention of making a profit, and hoping that what you offer will also be something that they will be comfortable with.Most people can smell a hard-sell or a "technique" from a mile away.I've never done what you're doing, but I can be empathetic with the people you would be approaching. 

Great question: to answer it we need to understand or make an intelligent guess who are the investors: If I were to say equity yield chasers  - Florida and Texas. 

Slobs like junk on their porch, and the slob that has their backyard crammed with junk while their front porch is bare is usually bad news.Ideally, you want reasonably intelligent people.

They are probably of lower intelligence and likely have extremely low social standards.Are they section 8 by any chance.

Even with all these problems, he is intelligent, interesting and truly a friend.

Why would any one of reasonable intelligence apply where they are not wanted.     

No intelligent  landlord would choose to keep a tenant they will need to evict more than once.

I've also noticed that the lower their intelligence, the more keen they are on telling me what to do and how to do things.

That way, in time you will know enough to either do the work yourself or intelligently hire it out to at least know when you are getting a reasonable price and if the job is quality or garbage. 

This guy won't pay anything close to market- he enjoyed milking his artificially low rent control price.