To know how a burglar might approach your house, get inside their head. Walk around the outside of your home once or twice with the mind of home invader. Think: "If I'm a burglar, which windows look easy to break or climb through?" Then look through the windows. Can you see expensive items that might tempt a thief? If so, you've got some rearranging to do.
After doing your homework, make sure each of these windows has locks, and curtains or blinds that can be drawn when you're not home.