With two lights, the most useful portrait setups are:

1. key + fill: Put the key light about 45° to one side of the subject, and place the fill near the camera axis. Make the key about 1–2 stops brighter than the fill for shape and contrast. This is a classic, flexible setup.

2. key + hair/background light: Use the key at 45°, then use the second light overhead as a hair light, or behind the subject to add separation and/or light the background. A reflector can replace the fill.

3. key + rim/kicker: Use the key in a softbox or umbrella at 45°, and place the second light behind and to the side to skim the head and shoulders for a dramatic rim effect. A reflector can again provide fill. You may need a flag/gobo to keep the rim light from flaring into the camera.

Which is “best” depends on the look you want: key + fill is the safest general-purpose choice; key + hair/background helps separate the subject from the backdrop; key + kicker gives a more dramatic portrait.