As simple as it sounds but keeping a property log and rent schedule is one the best way to keep a track of how well a tenancy is progressing.

A property log lets you track visits,  correspondence and complaints with the tenant.  This can also be used to track missed visits, warning issued and complaints which you may need if you need to take action against your tenant or if you receive a complaint about your management.

Property log 

A rent schedule lets you spot any arrears early and provides vital evidence should you need to take action against the tenants due to arrears.

Rent schedule