Room safety (hotel)
Keep your room locked at all times even when you’re in it. The same goes for windows if they are easily accessible from outside or small children can get to them from inside.
It’s also often a good idea to indicate your room is occupied even when you are out. You can do this by using a "do not disturb" sign or leaving the lights on.
If you’re staying somewhere you don’t feel particularly safe (and this won’t apply to most holidaymakers) try and get a room with a peephole so you can see who is outside before you open the door. And you can also place a wedge under your door if you feel really uneasy.