One simple rule he follows is that the only time a door should be unlocked is when someone is walking through it, Holsinger said. That includes when people are out working in their yards, he said.
One method con artists use to get inside a house is to distract a homeowner by asking directions or by pretending to sell something while an accomplice enters the house, Holsinger said. Someone intent on robbery or other violent crimes might use the same ruse, he said.
"Don't be so quick to unlock the door and open it," Holsinger said.
If a person comes to the door asking to use the telephone, the homeowner should offer to make the call for them, rather than let the person inside, he said. That allows the resident to help the person without putting themselves at risk, he said.
If a service provider comes to a house to perform a job the resident is unaware of, that should raise a red flag, Holsinger said. The resident should ask for identification, then call the company to confirm that it is a legitimate service call, he said.
"Once they open the door, they are susceptible to whatever's on the other side," Holsinger warned.
To see who is on the other side of the door, Holsinger said a peephole with a wide-angle lens is useful. To keep someone from getting through the door, a good deadbolt lock in a sturdy door and frame will stop or delay someone from getting inside.
If it takes minutes instead of seconds for a criminal to gain entry, that gives a resident time to call for help and for police to arrive, Holsinger said.
The "crime triangle" is desire, ability and opportunity, Holsinger said. Taking away easy opportunities makes a homeowner a harder target, he said.
Alton had a few more tips, such as good outdoor lighting and being aware of suspicious activity in the neighborhood, such as any strange vehicles parked on a street, particularly if it is occupied.
"It's all about habit building," Holsinger said.