Practice regularly the three types of portrait lighting mentioned above till the placement of lights become second nature to you. Remember what I have mentioned Outdoors, use the sun as your main light using the hard harsh light; then place a large white ‘diffuser’ between the light and the subject; notice the ‘softness’ as you bring the diffuser closer to the subject. The way to learn is to experiment. Do not be upset if you fail. Remember, he who does not fail, does not learn! Good luck.