Never hide house keys under the door mat or a rock that is near your door. Most burglars know that trick. Instead give an extra key to a trusted neighbor.
When you move to a new house or apartment, have a competent locksmith re-key the locks.
Don't use door chains; they break easily and do not keep intruders out.
Many burglars will spend no more than 60 seconds attempting to break into a home. Make sure every external door has sturdy, wall-installed dead bolt locks.