Never hide keys above the door header, or under the door mat.
Never hide keys around the outside of your home. Keep your keys in your possession at all times.
Be aware of bump keys and how easy it is for anyone to obtain them. Upgrade your locks or rekey them to render them bump resistant. Render bump keys useless by upgrading your most vulnerable doors to high security locks that include secondary locking designs that cannot be compromised by bump keys.
Always be aware that it is just as important that you can exit your home safely as it is to keep unwanted people out. Especially with youngsters and the elderly, it is important that a fire safety plan include knowing the safest path out of your home in the event of a fire.