1. Mow The Lawn. If you are in charge of the landscaping at your rental property, then mowing the lawn at regular intervals can help to reduce the risk of a break in. Often, criminals will look for signs that a house is not currently in use. One of the main signs of this is an unkempt lawn. An unmowed lawn, a garden full of weeds, wildflowers sprouting randomly, all of these things are like magnets to people with criminal intentions. Think of the local "party house" in your town. Most areas have a couple of buildings that are covered in graffiti and have most of the windows broken out of them. Look at the land around this building. Now do everything you can to make yours look like the exact opposite.
2. Take Out (Or In) The "Trash". If you are in the habit of leaving things outside, you may want to reconsider. Leaving things like ladders outside means that not only do you have something to take, but you're basically inviting a burglar in! Not only does it normally look less tasteful to leave a bunch of stuff outside that you normally see in a basement or garage, but they may turn into tools for someone to use to break into your home. Even if that doesn't happen, you still run the risk of having these things stolen since they are outside.
These are two simple things that you can do to help keep your home or rental property safe. Doing these costs little to no money and while they may be tiring, they are more than worth the safety that you get in return for the actions. Remember to check outside and try to see your home through the eyes of a criminal.