First let's start with a foundation of understanding. God created the heavens and the universe. He created natural laws and spiritual laws. These laws work just like the law of gravity works. The law of gravity works the same with a righteous person as it will work with an evil person.
I can tell you how witchcraft, divination and soothsaying work because I understand how prophecy, words of knowledge, discerning of spirits and other spiritual gifts work. If a righteous person drops a big stone on a pile of rocks he is using to make a wall, the rock will fall at the exact same speed and hit with the exact same force as it will with an evil person. The only difference might be the target. For example, the evil person may choose to use the same object for an evil motive. He may choose to use the stone in the same manner to take someones life or harm another person. The natural law governing how the stone falls can be the same. The only difference is the person's motive and target in exercising that natural law.
It is the same with spiritual laws. Spiritual laws work the same way as they do in the natural world. The main issue is what's the motive and the target of the practitioner.
The truth is there is a lot more witchcraft practiced today than many realize. I'll use the following scriptures to help explain.