Treat them decently and try not to be a lowlife scumbag slumlord like the vast majority of landlord scum that scumify the scummy rental business and also keep the place in good shape, performing the maintenance for which the tenants are paying good money, without complaint or unnecessary delay unlike the vast majority of whiny, greedy, scumsucking, scumsliming pigs that become landlords. Other than that, demand a ridiculously high security deposit.