-Ask for professional and rental references, and call them - in some cases, bad tenants are serial offenders.
-Get first and last month's rent in certified cheques.
-Consider asking prospective tenants for a credit report.
-Keep at least three months worth of mortgage payments and associated costs (utilities, insurance) in the bank to account for periods of vacancy.
-Understand your province's landlord and tenant laws.
-Have your tenant sign a rental agreement with any stipulations you may have (no smoking, no loud noise after a certain hour).
-Consider a rental insurance policy (and encourage your tenant to get insurance too).
-Schedule annual inspections to make sure the property is being well-maintained.