This point may seem obvious. But remember, the burglar is always going to look for the path of least resistance. If he spots an open window on a vacant home, that alone may be the reason he picks your house. If he can just open the back door, without kicking it in, without resorting to a bump key or picking the lock, his job becomes far easier. And burglars will and do enter homes through windows. So keep them closed, and keep the latches closed.
Although 95% of the deadbolts in this country can be opened with a bump key, it’s also true that burglars will look for doors without deadbolts. These provide the easiest possible targets. So if you don’t already have them, make sure to install deadbolts in every entry door into your house!