The most common method of entry was breaking out a window or the glass in a door. According to Seattle Police:
Burglars usually break in through rear and side doors. If you have the old-fashioned, glass on top and thin paneled on bottom doors, consider replacing them with solid core doors.
Or, police say, you can reinforce the existing door by screwing Plexiglas or Lexan over the window and exterior-grade plywood over the bottom panel.
Rear and basement-level windows are especially vulnerable. Unless they are part of your fire escape plan, they should be fitted with special window locks.
And use a timer, especially during this dark holiday time of year.
A dark house in the late afternoon or early evening looks unoccupied and become more attractive to burglars.
You can download more information from the police about home security here: home security tips (pdf).
Here’s more information online from the police department.