This is one of my first attempts at a head shot after watching many hours of instructional videos on the web.
One light was used - a speedlight in a 40" reflective umbrella. I tried to keep it angled away from the background so that the background would remain dark. The shooting area was too small to move the model far from the background. A reflector was balanced on the model's lap to provide fill. A large black foam core board was used for the background. The camera was a Canon 70D in manual mode. ISO 200, f/7.1, 1/200sec. The flash was set to manual too.
Both global and local adjustments were done in Adobe Camera RAW. Light retouching was done in Photoshop and PortraitPro was used for a tiny bit of skin smoothing.
Nice you didn't catch the light in the glasses.