Firstly, the Insurer should be notified that the property is rented to tenants, and not occupied as your private dwelling. Other covers specific to a rental property policy include Loss of Rent (needs to be adequate to cover level of rent you are receiving), Property Owners Liability (extension of public liability to note you have tenants), cover for casual Property Repairs & Maintenance persons necessary to keep the rental property in good order.
Also, it must be noted that basic Home Insurance (even a policy for Landlords) is based on a Fire & Perils policy wording. This may not be enough for an investment property though. Property Damage All Risks cover should be considered which gives much broader cover, and this is important where a property is no longer in the (daily) control of the owner i.e. it’s let out to tenants.