In most cases landlords prefer to talk directly to their tenants about any problems and to come up with a solution. It is however often a good idea to back up such conversions in writing. This not only demonstrates your professionalism but also proves an evidence base should further action be required.
Before any property visits you should provide your tenant with written notice, even where its agreed that you will visit at a pre arranged frequency.
If you get a compliant from a neighbour, the council or the police about anti social behaviour (ASB) in one of your properties you should take the compliant seriously. Its a good idea to talk to your tenant to hear their side, but you should make sure you are clear you will not tolerate ASB and should issue a letter after every conversation to show you are serious.
The earlier you spot rent arrears the easier it is to prevent and reduce. If you tenant falls behind you should talk to them to understand why, if they've had a change in financial circumstances they might be struggling and you should refer them to the Council for benefit and debt advice.