Learning flash can be a tough endeavor; it takes a combination of a lot of technique, attention to detail, and creative vision. If you are working on mastering flash, check out this fantastic video tutorial that features an experienced photographer sharing perhaps the biggest mistakes photographers make when working with flash.
Coming to you from Jiggie Alejandrino, this awesome video tutorial discusses a common mistake flash photographers make: overcomplicating the endeavor. This can even mean using flash when ambient light is not only sufficient, but even more flattering. There is a tendency to create complex lighting setups simply for the sake of being complex, but it is important to remember that the aim is to create lighting that fits the best for scenario (and preferably accomplishes that in the most efficient manner). Like a virtuoso musician, just because you can shred a ton of notes does not mean it is appropriate for the musical context at any moment; sometimes, subtle is better. Check out the video above for the full rundown from Alejandrino.
If you would like to continue learning about how to light a portrait, be sure to check out "Illuminating The Face: Lighting for Headshots and Portraits With Peter Hurley!"