Class C property, what income/rent ratio do you require?

[Mauricio Quintana]

Landlords of class C properties,

This is my first venture into rentals.  I'm just curious as to what parameters you use to determine a good renter?  Do you do any sort of ratio where you look for 3x (or whatever that multiplier is) in income versus the rent amount?   

Any other particular "red flags" you look for in their rental application that have come back to haunt you?  Outside of the specific rent multiplier question, any other insight/advice would be greatly appreciated

Thank you