You will need:

1. Uncap your Sharpie® brand permanent marker.

2. On the blank sign, inscribe the following in large, menacing letters:

WARNUNG VOR DEM HUND

3. Display your sign in a place of prominence near your home's entrance.

4. Kick back and relax with a nice frosty Löwenbräu, knowing any wandering Germans will think twice before hopping your picket fence.