What are the signs of sorcerers, fortunetellers and soothsayers? How can we tell who they are?
Question

                How can we known the sorcerers and charlatans, and those who use the Qur’aan as a remedy? Is it permissible to ask the Muslim jinn for help? Could you send me some of the du’aa’s that are narrated from the Prophet for the one who is suffering poverty or who is finding it hard to make a living? Can you tell me about the magic which causes poverty, and is it possible to avoid it and rid oneself of it?
Praise be to Allah.The sorcerer and charlatan may be recognized by a number of things, among the most important of which is: his claim to know the unseen; even if he does not state that clearly, you will find that he speaks of matters of the unseen which may all be lies and falsehood. Some of what he says may come true but most of it will be lies, but the lies will be overlooked because of the few things that come true. Similarly, there will be a lack of righteousness, for you will not find them to be keen to worship. They are often exposed, especially in their lies, and in matters that have to do with women. It often comes to light that they have committed haraam actions involving women, such as being alone with them, or touching women using the excuse of healing.                                                                               
Shaykh Sa’d al-Humayd.
Another sign of the fortunetellers, sorcerers and soothsayers is that they will ask for the name of the person who has come to them; they often use bukhoor (incense) and strange materials; they may write Qur’aan with impure substances and menstrual blood; they may ask a person to offer a sacrifice to someone other than Allaah; they use large rings; they may not do ghusl after janaabah (impurity following sexual activity); they may mutter strange and mysterious words; they may use secret signs and charms; they may pretend to recite Qur’aan in the beginning to deceive the person who has come to them. 
We ask Allaah to protect us from their tricks, for He is the Best of protectors and the Most Merciful of those who show mercy.