Be attentive to how you are perceived by local people and behave in a manner that is neither provocative nor draws unwanted attention.
Familiarize yourself with your foreign neighborhood and work environment.
Use street smarts. Beware of pickpockets, scam artists, over-friendly strangers, loiterers, etc.
Take a seat on a bus or train that allows you to observe fellow passengers.
Educate yourself of any pending events (elections, demonstrations, anniversaries) that may cause civil disturbance, and avoid unnecessary risks. Do not photograph anyone at these events.
Establish a support network among your colleagues and US embassy personnel in your host country.
Confirm with the US embassy the procedures for you and your family in the event of a crisis or evacuation.
To avoid being drugged, politely decline offers of food or drink from strangers.