Tip #1: Know where to walk.
Obviously this is an important one, but the most obvious answer is the sidewalk...and that would of course be the correct answer as well. But German sidewalks aren't always as simple as American.
most of them are for bicycles as well. The easiest way to tell is the color difference, both sides will be of different color stone/cement. The section closest to the road is for bicycles, the one furthest from the road is for walking.
