These pictures are easy to take because existing daylight is usually brighter than other kinds of existing light. Avoid poses that put too much of the face in shadow, unless you want a special effect such as a silhouette. You can also photograph your subject in direct sunlight coming through a window. This type of lighting is bright, but it is also contrasty. Watch out for deep shadows on your subject.
Some artificial lighting is also quite contrasty.
For pictures in existing tungsten light at home, household lamps with translucent shades are best. Translucent shades let light through and provide more uniform illumination for picture-taking than darker or opaque lampshades. Pose your subject so that light illuminates the front or side of the face. You can reduce excessive contrast by adding light to the shaded areas of the subject by bouncing light where it is needed. The more efficient the reflector and the closer it is to the subject, the more shadows will be filled with light.