I recommend you beef up your house rules. Peruse this forum for some of the things hosts have gone through and take it from there.
Also make sure you have somebody close by with an eye on the property.
For longer rental periods have somebody come by once or twice a week at a set period to bring fresh linens and cast an eyeball over the condition of the apartment. Announce this in your description too.
That should keep the likelihood of your home getting trashed or being inhabited by more inhabitants than booked for to a minimum.
Make it a point to lock away any valuables (jewelry, firearms, heirlooms, etc) or special items you would prefer not be used. You should already have an inventory of valuable things to go with your homeowners insurance, so shouldn't be much work.