landlord 101
I had a rental house for 6 months. I bought a new house and figured I'd "clean up" renting the old place. I cleaned up alright. They trashed the house and when they moved out I sold it. I could completely rebuild the place every 6 months.
A friend of mine has multiple rentals and has for years. He said when someone applies for the rental, they are always the third inquiry. That way when you don't rent to them they can't sue you for discrimination. "Hey, I rented to one of the first two there before you."
Also he always pulled a credit report on a potential renter, and then asked them what he could expect to see.
Number 5 above, the appropriate security deposit, make the deposit not as much as the rent. That way when the lease is up or when they want to bail, they can't say, oh we'll just not pay the last month and forfeit the deposit.
Good luck with all this. I wouldn't do it again.