Know the fire angles in your house. Know when and WHERE to shoot from, and toward, and not shoot.
If someone attempts comes in door A, where the best place to shoot from? Door B? The garage?
Analyze the construction of each interior door, floor or wall in your house, as well as exterior doors and walls. Bullets will penetrate Sheetrock, particle board, plywood, 2 x 4s or lath and plaster. They won't easily penetrate brick, stone or concrete, or heavy steel doors.
In other words, if you needed to, could you PHYSICALLY shoot through the wall in room A and hit someone in room B? If you were in the basement, can you shoot through the basement ceiling / ground floor floor and hit someone on ground floor? If in a multistory can your shoot through the first story ceiling into the second story floor?
If you point a gun at intruder, and he drops behind cover such as couch, sofa, bookcase, armoire, etc, choose the best angle and shoot THROUGH the furniture. If he ducks around a corner wall, and it's not brick, stone or concrete, shoot THROUGH the wall. If you and your family is all in the basement, and you can locate the intruder on the ground floor by his footsteps, shoot THROUGH the basement ceiling.
Make DAMN sure your family is secure in another area before firing blindly, though. Blind firing can be very risky, so think it over carefully before you decide to use such tactics.
Replace all exterior doors, the door leading into the garage, and the door(s) leading into your primary bedroom, with steel framed, steel construction doors.
If you're handy with tools, you might construct some homemade Fox Police Locks. There were two types, the door mounted and the Floor Mounted. The floor mounted were the most secure, and they actually had a cutout into the floor where the bar fit. The original company is out of business, but you could make ones for each door if you have the talent. Some companies make copies. Google "Fox Police Lock".
http://www.nytimes.com/2008/04/27/nyregion/thecity/27lock.htmlhttp://www.nokey.com/foxstylpollo.htmlhttp://www.nokey.com/orfoxstflmop.htmlhttp://www.sears.com/abs-cwlocks-2723-original-fox-style-police-lock-double/p-SPM3744613801P