Expanding on the diamond technique.
In the facial anatomy chapter of How to Draw Black People, I demonstrate how a diamond shape can be used to build a facial grid from the inside out. It's something I call the diamond method. What makes the diamond method most useful is it's versatility. Treating the shape as if it were three dimensional gives me important information for planning out a pose.
In my demo, I use the line tool in Clip Studio Paint to create the diamond and the facial grid but once you are more comfortable with the principles of the diamond method you'll be able to forgo most of the steps and rely on the shape itself to inform your decisions.
Reference is your friend, however, keep the phenotype identifiers in mind and remember that Afrocentric noses can tilt up or down and the nostrils can be wide or narrow. Avoid cliches and stereotypes. Resist relying on the size of the nose alone to convey the African phenotype.
The more comfortable you are drawing volumetric shapes, the easier the diamond method will be for you. When you feel more confident, challenge yourself by drawing the diamond shape from different angles.