A portrait is simple, right? Look at the camera and smile.
Not so much. Apart from the “smile” thing, there’s also angle. And the same person can look very different if shot from different angles.
Like me, a couple of days ago:
Can you see how they are all different, and yet the same person? Some work better than others. So when you do portraits, try all sorts of angles, and then analyze which ones work. Model the face (avoid even lighting, for interest). Watch for shadows and ensure you get good catch lights.
And note that all of these work better in B&W than they would in colour.
So…. try some B&W portraits from various angles, lit by softboxes.