Hazrat Moulana Ashraf Ali Thaanwi (rahimahullah) once mentioned:
In the path of seeking self-reformation, it is obvious that a person will be in need of a sheikh (spiritual guide to guide him through the path). However, since many people are unaware of the procedure to follow and the criteria to look for when selecting a sheikh, they err in selecting the right person for their islaah (self-reformation).
Hazrat Thaanwi (rahimahullah) thereafter mentioned that the following criteria should be found in the person one wishes to take as his sheikh (spiritual guide):
1. The person should be well acquainted with the laws of shari’ah, though he may not be an aalim who is an expert in every science of deen.
2. He must have knowledge of the path of tasawwuf and sulook, though he may not be a person who experiences kashf, nor a person from whom miracles or supernatural acts are witnessed.
3. He must have spent a considerable amount of time in the company of a sheikh-e-kaamil (a pious spiritual mentor who has completed his islaah under his mashaaikh)
4. When sitting in his majlis, the general effect that one finds is that one’s love for the dunya decreases and a yearning for the Aakhirah is created (or increases) in one’s heart. Similarly, fear for getting involved in sins and the motivation to carry out good deeds is created in the heart, regardless of whether one experiences any spiritual conditions or not.
Despite the person being a sheikh-e-kaamil, if one does not perceive any benefit through remaining in his company, then one should realize that the reason for this is that one does not have compatibility with the sheikh. Therefore, one should leave this sheikh and seek another sheikh.
Nevertheless, even when one does not find compatibility with a particular sheikh, he should not show any form of disrespect to him. This can be compared to the situation where a certain doctor’s treatment is not proving effective for a person. In such a situation, one will refer to another doctor, but an intelligent person will not run-down or disrespect the first doctor.
(Malfoozaat Hakeemul Ummat 24/323)