Keep your doors and at least your first floor and basement windows locked, especially if no one is home.
Check to see who is knocking before telling them to “Come on in!”
Be aware of all visitors in your home. Do not let anyone in your home you do not know. Even if you are having a party. try to limit your guest list to only close personal friends.
Never give anyone, aside from your roommates, your schedule as to when you will or will not be home.
If you have a large window on your front door, cover it with a curtain.
Make sure you pick up all advertisements from the front yard or on the front porch. An accumulation of them can give the appearance that no one is home.
Get to know your neighbors. Not only will you gain new friends. but you will also get the added bonus of additional people looking out for you and your property, especially when you are away.
Do not leave ladders or other items someone could climb on laying around outside the house.
If you have an alarm system, use it.
Have security lights installed, and replace bad bulbs as needed.
Have all broken doors and windows repaired.
If a set of keys comes up missing have the lock replaced.
Keep bushes. shrubs, and trees trimmed back so they do not block widows.
Make every effort so it appears some-one is home, even when they are not. Leave a light and a radio or TV on in the house.
Buy timers for lights in your house so you are not coming home to a dark house at the end of the day.