Most thieves are desperate people who just want to come in and out of houses to get the valuables they can sell with as little effort and risk as possible. This means that one of the most effective approaches you can take to keeping them out is simply to make sure that you make your house highly unattractive to burglars so that they don't bother trying in the first place.
Lock Down Your Sliding Doors Properly
It's common for burglars to just pop off the screen to sliding doors to get in. It's also common for people to use less than the best locks for sliding doors specifically. It helps to go to a locksmith who can help you choose locks and other security measures designed for this entrance area in specific. This could also include putting a bar in the sliding area at the bottom so the door just won't open.
Lock Upper Story Windows
One common easy tactic thieves use is that if the bottom floor windows and doors won't open, they instead find a few good handholds at some area of the house and hop up to the second floor. Many burglars have been known to climb up a nearby shed and then jump to a second story ledge in a building. The reason for this is because many people don't lock windows on the second story of houses. They figure that these areas are safe.
The truth is that this isn't the case. If you keep these windows locked whenever you go out, you'll make the house much less tempting for burglars.
Set Automatic Lights
There are a lot of automatic lights these days that will come on during certain points in the evening in order to make it harder for burglars to tell if there's anyone home. Lights that illuminate the outside of the house can also go a long way to making it difficult for burglars to approach the house without being seen, or at least without being intimidated into leaving.
Many security firms will allow you to buy security stickers in order to make it look like you're protected even though you're not. It's free advertising for them, and it only costs you a tiny amount of money in order to get free deterrence against any would-be thieves. Overall, this can be an effective way to prevent thieves from even trying to steal from you in the first place.