Make Your Home Unattractive to Thieves
Anyone who works in the security business will tell you that if a thief really wants to get into your home, he probably will. However, there's good news here. Most thieves don't want to get into your particular home, they just want to get into a home. So the trick becomes making your home less attractive (let's say harder to get into) than someone else's.
You can make your home unappealing to a potential thief in a number of ways. You can install alarm systems and spend hundreds of dollars for ongoing monitoring. Alternatively, you can hire a security company to actually drop by and check out your home on a regular basis. Or, you can hang onto a lot of money and do some low-cost, but effective, deterrents all by yourself.
Start With Locks and Doors
Entrance doors are obviously the easiest way to gain entry. In many homes, a hard swift kick on the front or back doors will literally drive the door right out of its frame and the thief can just walk in and help himself. Most homes are originally equipped with inexpensive spring latch locks that have a short rounded locking finger that slides into the casing around the door. Upgrade your locks by removing what's there and installing dead bolt locks. Even better, double dead bolt locks (that need a key to be unlocked from the inside) provide the best security.
Good dead bolt locks have a "throw" (the metal finger that sticks out when it's locked), about an inch long that actually goes into the door frame, not just into the light wooden casing around the door. Dead bolt locks are available at your local home store and they come with easy to follow installation instructions, but if you're uncomfortable changing locks yourself, a good handyman can do it for you.
Upgrading locks are a great start, but don't forget the screws holding the lock and door hinges in place. The strike plate on your door jamb and the hinges on your door are probably held in place with screws that are about 1"-long, just long enough to fasten into the casing lumber. You can upgrade the strike plate with a much longer strike plate 10" or 12" and install it with 3" screws. These screws are long enough that they will go right through the door casing and into the 2 x4 or 2x6 framing lumber around your door. The longer strike plate will also accommodate six or eight screws for fastening it. Remove the short screws fastening your hinges as well and replace them with the 3" screws, and your door will now be firmly fastened into the door frame. No one is going to kick that door out of its frame.
Don't Forget Your Windows
Patio doors and sliding windows are relatively easy to get out of their frames. A thief could do it by just lifting it up out of the frame (works just as well from the outside as it does when you lift them out for cleaning from the inside). The way to fix this problem is to drive a few screws into the top track above where the door or window sits when it's closed. The trick is, don't drive the screws all the way in, leave the screw heads protruding about 1/4". The protruding heads make it impossible to lift the door or window up high enough to lift the bottom out of the frame when it's closed. You can still remove the door or window for cleaning by sliding it over to the open position (where there aren't any protruding screw heads) and just lift it out of the frame.
You don't need to do anything very fancy to stop windows and doors from being slid open. The old reliable idea of a "stick in the track" effectively blocks them from being slid open. Cut a piece of dowel (about 3/8" diameter) to fit into the track. When you're inside, you can easily pick up the dowel in the track, but its round shape makes it hard for someone to dislodge it from the outside. Paint the dowel to match your window frame and it will virtually unnoticeable.
You can prevent these from raised form the outside by drilling a small hole through both the window casing and the window frame and sliding a nail painted to match the window into the hole. Simple easy and very effective
Casement and Awning Windows
Securing these designs requires installation of locks specially designed to prevent these windows being swung open. Locks are available that will either prevent the handle from being turned or fasten the window to the frame. The design that actually secures the window to the frame would seem to be more secure. Again these locks are available at your home store and are easy for a DIY'er to install themselves.
No matter what style of window you have in your basement they're always going to be a challenge to secure primarily because of where they're located. Break resistant glass and pins or locks securing the window to the frame will definitely help, but security bars are probable the best defense. Decorative bars that can be painted to match your home's trim are available and if you use them, your home won't look like a branch office of the state prison.
It Takes More Than Locks
Burglars don't like to be seen, so install lights that will light up the outside of your home. Motion detecting fixtures are a great idea, just be sure to install them where a burglar can't reach up to remove or break the bulb.
Plants and shrubs growing around your home can provide a great place for a burglar to lurk unseen. Keep your bushes trimmed so a burglar can't hide in them, out of sight.
Don't advertise that there are things worth stealing in your home. If you get a new TV or computer, don't just put the box out by the curb on trash pick up day and let the bad guys know what's inside. Break down the box or turn it inside out, so no one passing by will be able to make a shopping list.
Finally, make sure your home has a lived in appearance. Plug interior lights and a radio into timers that turn on and off at different times so your house looks occupied. If you're going to be away for a while - make arrangements to have your grass cut (or snow cleared), stop mail and newspaper deliveries and have someone pick up those flyers that seemingly show up every day. Getting a neighbor to park a vehicle in your driveway also helps make it look like someone is there.
Unfortunately, there's no guarantee that if you do everything suggested here that your home won't ever get broken into. However, following these suggestions will definitely make it more difficult for a burglar to get into your home, and often that's enough to get him to try somewhere else.