Croatia is not a dangerous destination and it is possible to walk about, day or night, without feeling apprehensive, even for women alone.
Use your common sense, lock your door and your car, don't leave valuables lying around, particularly on the beach and if you consume a lot of alcohol be careful you are not breaking any laws.
Unauthorised camping is forbidden and you will be fined if caught by the police. Otherwise, campsites are very similar to ours. The organization is generally very good.
When swimming be careful of sharp rocks and sea urchins; use water shoes to protect your feet. If you like diving, you need to have a permit to do this. Get one before you go diving.
If you are going for a walk stay on the marked path and don't go off-road. A few mines dating back to the Serbian war can still be found hidden in some areas. These are dangerous areas to walk around (don't worry too much as they are always off-road areas and it is easy to walk the length and breadth of the country without incident).