Arrival by plane
You should arrive during daytime if possible. If you are travelling to high-risk destinations, this may be very important indeed.
Have your transportation from the airport pre-arranged: pick-up by a colleague, a friend or a well-reputed taxi company. Make sure you have some way of validating the identity of your contact if he or she is not known to you.
Alternatively book your taxi at the taxi counter in the airport instead of flagging one down outside Arrivals. NEVER use gypsy taxis, and never accept additional passengers unknown to you.
Learn the local traffic rules. Self-driving in many developing countries should be avoided as the foreign driver often will be considered the guilty part, and even a minor accident can lead to instant reprisals and/or long legal cases.
In some parts of the world, stopping at intersections and red lights is dangerous, e.g. Johannesburg.
When renting a car, do not go for the exotic. Often criminals will target certain brands or types, like SUVs.
Use only registered taxis. In some countries even registered taxies cannot be trusted. Find out which taxi company you should use or preferably book a taxi to be waiting for you when you arrive at the airport.
NEVER use taxi touts, and never accept additional passengers unknown to you.
Ask the hotel front desk to call for a taxi; do not hail them in the street.
Make sure the taxi uses a meter. If there is no meter, the fare should be negotiated before you go.