How to achieve a broad light shot…
One of the best ways to make your selfies attractive is to experiment with lighting, different angles, and positions. The photo above is by @rrebelliouss , the background is slightly illuminated, but the main source of lighting is to the top left. Having the light slightly above usually has the effect of eliminating unflattering shadows. Turning your head about 30 degrees away will focus the light on the broadside of your face, hence the term broad light. This creates a slight shadow on the far side of your face, and under the chin.
I recommend experimenting with this and see the results you get. Also, bring your ears/chin slightly forward can help give you a more defining jawline. The result is typically a more dramatic look. I am a huge fan of smiling because I believe it’s contagious and it puts the viewer in a positive mood. but in this case, she went for a more subtle expression which created an adorable look.