Before your tenant moves into the unit, you should inspect the premises. Some states actually require you to describe the condition of the rental in writing and provide a checklist for each unit. LegalZoom provides you with a standard move-in/move-out checklist as part of your custom lease package.
When describing the unit, clearly identify all of the features, from window treatments to flooring. Next, identify the condition of each feature. List the scrapes, scuffs and other imperfections, as well as any upgrades you've made to the unit. Are there new appliances? Have you repainted or re-carpeted? Did you install a new garbage disposal? A formal move-in checklist helps avoid disagreements down the line should you need to withhold funds from the security deposit to cover damages.
At this point, you should also take photographs of the unit before the tenant moves in. By documenting improvements and existing features, you can easily identify any changes, including damages to the unit at the time of move-out.