To achieve his goal, Shaytan first lures mankind into Shirk and Kufr, such as visiting graves and invoking the dead or saints for help, practicing magic, etc. because associating partners with Allah is the greatest sin. 'Like when Shaytan says to man, 'Disbelieve in Allah.' But when (man) disbelieves in Allah, Shaytan says, 'I am free of you, I fear Allah, the Lord of the Alameen (mankind, jinn and all that exists).' [Soorah al-Hashr (59): 16] If Shaytan overcomes the son of Adam with this and succeeds to make him a disbeliever, then he is satisfied and pleased.
If he cannot manage to deceive people into committing Shirk and Kufr, he does not give up. He causes people to follow bidah (innovations) and take them as their religion like celebrating Mawlid, celebrating the night of Isra wal-Miraj, celebrating 15th Shabaan by fasting and praying and as Sufyan ath-Thawri said, 'Bidah is more dearer to the Shaytan than sin, for, one may repent from sin, but not from bidah.' Because when one sins, he knows that he is disobeying Allah and some time, he may turn to Allah and seek forgiveness and be pardoned. But one, who practices Bidah, deems his actions to be a form of worship to Allah and thus never even thinks of repentance. 'Say (O Muhammad), 'Shall We tell you the greatest losers in respect of (their) deeds? Those whose efforts have been wasted in this life while they thought that they were acquiring good by their deeds!' [Soorah al-Kahf (18): 104] meaning, 'they performed deeds that do not count, deeds that are not in accordance with the prescribed way that is acceptable to Allah' and 'they thought that there was some basis for their deeds and that they were accepted and loved.' [See, Tafseer Ibn Katheer]
If Shaytan fails at causing people to following innovations, he will move on to calling them to major sins like abandoning prayers - particularly if the person is well educated or respected, because a lot of people will follow his example. It is mentioned in the Qur'aan, 'Shaytan wants only to excite enmity and hatred between you with intoxicants (alcoholic drinks) and gambling, and hinder you from the remembrance of Allah and from As-Salaat (the prayer).' [Soorah al-Maidah (5): 91]
However, if the believer withholds, Shaytan is still not discouraged, he calls them to minor sins. It is recorded in Sunan Tirmidhee (2/230 (no. 1753), 'Shaytan has despaired of ever being worshiped in this land of yours, but he will be obeyed in matters that you think of as insignificant, and he will be content with that.' And Allah's Messenger (sallalalhu alaihi wa-sallam) warned us concerning minor sins by giving an example of how a great fire can be kindled if small wooden sticks are collected in a place. Similarly, minor sins if allowed to accumulate, might destroy a sinner, he (sallalalhu alaihi wa-sallam) said, 'Beware of the insignificant sins like a people who stayed (abode) in a valley, then this one brought a stick, that one brought a stick and others brought sticks too until they cooked their bread (meal). Verily, the person who commits these (minor) sins will be seized by these sins and be destroyed.' [Musnad Ahmad]
If the believer still emerges safe from his traps, Shaytan seeks to keep him occupied with permissible matters, like sleeping, eating, pursuing worldly affairs, etc. Spending one's time and efforts in these will earn him neither reward nor punishment, though he will miss the rewards he would have gained if he has spent his time in performing good deeds. If the believing slave is not deceived and manages his time well, Shaytan will make him busy with less virtuous deeds instead of what is more preferable and rewarding, in order for him to miss the reward of the best and most virtuous deed.
After employing all kinds of temptations and deceptive arguments, if Shaytan still does not succeed in his endeavors to divert the children of Adam from religious commitments, he resorts to corrupt their acts of worship and obedience, so that he can deprive them of the rewards. He seeks to stir up doubts in order to make a person feel anxious and uncertain. In Saheeh al-Bukharee, it is narrated from Abu Hurayrah y that the Messenger of Allah (sallalalhu alaihi wa-sallam) said, 'When the call to prayer is given, the Shaytan runs away breaking wind loudly, so that he will not hear the adhaan. When the call to prayer ends, he comes back, but when the iqaamah starts, he runs away. And when the prayer begins, he comes back until he whispers into the heart of the person, and says to him, 'Remember such and such, remember such and such things that he did not remember before the prayer until he does not know how many raka'ahs he has prayed.' [Saheeh al-Bukharee (608)]
Such whisperings of Shaytan are the weakest of his tricks. The companions of the Messenger of Allah (sallalalhu alaihi wa-sallam) complained to him (sallalalhu alaihi wa-sallam) that they noticed some waswaas that they disliked and did not want to speak of, and he (sallalalhu alaihi wa-sallam) said to them, 'Praise be to Allah, Who has reduced his tricks to whispers.' [Saheeh Abu Dawood]
If the person is undefeated even after this, the next step of Shaytan is to harm the person by, for example, persecuting him or distorting his reputation and his devotion to the religion. This is intended to discourage the person from his commitment to the religion. Many scholars have been tortured or killed in prison because of their commitment to Islam!!