Though, with practice, one can experiment with light sources that are elsewhere such as between the subject and the photographer.
Having said that, it is generally not advisable to take photos when the source of light is directly above or in front or behind the subject since the resultant photos may have too many shadows.
Therefore, walk around the subject and see how you can position yourself or your camera to take the best possible photos.
As you do so ensure that the brightest part of your photo is the subject since the eye is always drawn to the light within the frame.
After finding the light, see if you can play with the light for example by creating a silhouette. This can be done by having a brighter light source behind the subject.
You can also experiment with side lighting which creates contrast and shadows that add depth to the photo.
When taking photos outside, ensure that your subject is in the shade since sunlight can make them squint, appear darker and harder to differentiate from their surroundings as well as create shadows like in the picture below.