I may get flamed for this, but walk facing the traffic, folks. If there is dirt or gravel next to the trail you should walk on that when the trail is busy. Seriously, whenever possible don't put yourself in a position where bikes are sneaking up on you or slaloming around you. Even a slow bicyclist is going a lot faster than you are walking.

I'm convinced ear buds are a disaster. When walking, running, bicycling your situational awareness is really important. If you have your back to the oncoming traffic and ear buds in, you make yourself sort of blind, deaf and distracted.