Carry out reference checks on the tenant(s) such as the services provided by the RLA. This will highlight any previous CCJ's the tenant (s) may have and confirm the details the prospective tenant has given you in their application.
Ask the tenant(s) for a guarantor. By having a guarantor you can contact them for any rent arrears problems that may occur during the term of the tenancy. A home owner and/or someone in stable employment is a good guarantor to fall back on if required. Credit check the guarantor(s).
Where your market allows, consider taking 6 weeks as a minimum for a deposit. This is hopefully a sufficient amount, for a month's rent arrears and any damages/cleaning that may occur at the end of the tenancy. Be aware that taking 2 months or more as a deposit triggers the tenant's right to sublet without your permission.
Protect the deposit (if taken) in a relevant scheme within 30 days of receipt of the deposit. Once the deposit is protected, ensure that all parties (parents, partners) that have contributed towards the deposit are given a copy of the Certificate, Prescribed information and Scheme Leaflet. Get a signature confirming that the tenant(s) have received this information from the Landlord/Agent.
Do not hand over any keys to the property until a tenancy agreement has been signed and the first month/week rent in advance and security deposit has been received.
Appropriate Insurance should be in place for Building, Public Liability and Rent Guard (rent insurance).
Complete an inventory (photographic) and make sure the tenant (s) sign to agree the condition of the property. If they do not sign the Inventory, write to the tenant(s) and give them 7 days to confirm back, otherwise it will be taken that the Inventory is agreed by both parties.
In England, at the start of the tenancy give the tenant a copy of the EPC, gas safety certificate and a copy of How to rent: the checklist for renting in England. You can't serve a Section 21 without serving this first.
Make sure you have smoke alarms on every floor of your property and carbon monoxide alarms in every room with a solid fuel source