Take and keep the attitude it's a business and run it as such. Tenants aren't your family or friends, they are buying a product from you, don't give it to them for free or at a discount just because they have a sob story, THEY WILL.
This is where I have trouble.
Imagine having to kick out a pregnant mom with a two year old toddler.
Get a management company to deal with the tenants, you can still live there, just don't let them know you own it.
Woman, esp. mommy like to have a place of their own, its a nesting thing. They can also be ruthless with power,,,,,sometimes.