Always have your headlights on
Even if you are living in a country where you are not obliged to use your headlights at all times, it is a wise thing to do so. A car with its lights on is much easier to spot on the road and thus increases your safety, especially when the daylight is weak due to clouds or the low sun activity in places lying very far from the equator.
Most of the new cars have the daytime running light installed, which uses much less energy. However, if you don’t have them in your vehicle, it is definitely worth considering to use your normal headlights during the day.