1 – Seek refuge with Allah from the Devil:
Sulayman bin Sard narrated:
“I was sitting with the Prophet, when two men began slandering one another. One of them was red in the face, and the veins on his neck were standing out. The Prophet said: “I know a word which, if he were to say it, what he feels would go away. If he said: “I seek refuge with Allah from the Devil,” what he feels would go away.'”
[‘Fath al-Bari’; 6/337]

The Messenger of Allah said:
“If a man gets angry and says: “I seek refuge with Allah,” his anger will go away.”
[‘Sahih al-Jami’; # 695]

2 – Remain silent:
The Messenger of Allah said:
“If any of you becomes angry, let him keep silent.”
[‘Sahih al-Jami’; # 693]

3 – Sit down or lie down:
“Abu Dharr was taking his camels to drink at a trough that he owned, when some other people came along and said to one another: “Who can compete with Abu Dharr in bringing animals to drink and make his hair stand on end?” A man said: “I can.” So, he brought his animals and competed with Abu Dharr and ended up breaking the trough.Abu Dharr was standing when he saw this, so, he sat down, then he laid down. Someone asked him: “O Abu Dharr, why did you sit down then lie down?” He said: “The Messenger of Allah said: “If any of you becomes angry and he is standing, let him sit down, so that his anger will go away. If sit does not go away, let him lie down.”””
[Reported in the ‘Musnad’ of Ahmad (5/152) and ‘Sahih al-Jami’ (694)]

al-Imam al-Khattabi said: “One who is standing is in a position to strike and destroy, while the one who is sitting is less likely to do that, and the one who is lying down can do neither. It is possible that the Prophet told the angry person to sit down or lie down so that he would not do something that he would later regret, and Allah Knows best.”
[‘Ma’alim as-Sunan’; 5/141]

4 – Smile:
Anas bin Malik narrated:
“I was walking with the Messenger of Allah, and he was wearing a Najrani cloak with a rough collar. A bedouin came and seized him roughly by the edge of his cloak, and I saw the marks left on his neck by the collar. Then the bedouin ordered him to give him some of the wealth of Allah that he had. The Prophet turned to him and smiled, then ordered that he should be given something.”
[‘Fath al-Bari’; 10/375]

5 – Remember the advice of the Prophet:
Abu Hurayrah narrated:
“A man said to the Prophet: “Advise me.” He said: “Do not become angry.” The man repeated his request several times, and each time the Prophet said to him: “Do not become angry.””
[‘Fath al-Bari’; 10/456]

According to another narration, the man later said: “I thought about what the Prophet said, and I realized that anger combines all kinds of evil.”
[Reported in the ‘Musnad’ of Ahmad; 5/373]

6 – Remember the high status of those who control themselves:
The Messenger of Allah said:
“The strong man is not the one who can overpower others. Rather, the strong man is the one who controls himself when he gets angry.”
[Reported in the ‘Musnad’ of Ahmad; 2/236, and it is authentic]

The Messenger of Allah also said:
“The strongest man is the one who, when he gets angry and his face reddens and his hackles rise, is able to defeat his anger.”
[‘Sahih al-Jami’; # 3859]
Anas bin Malik narrated

“The Messenger of Allah passed by some people who were wrestling. He asked: “What is this?” They said: “So-and-so is the strongest; he can beat anybody.” The Messenger of Allah then said: “Shall I not tell you who is even stronger then him? The man who, when he is mistreated by another, controls his anger, has defeated his own devil and the devil of the one who made him angry.””
[‘Fath al-Bari’; 10/519]

7 – Rewards for those who control their anger:
The Messenger of Allah said:
“Do not become angry, and Paradise is yours.”
[‘Sahih al-Jami’; # 7374]

The Messenger of Allah said:
“Whoever controls his anger at the time when he has the means to act upon it, Allah will call him before all of mankind on the Day of Resurrection, and will let him choose of the Hur al-‘Ayn whoever he wants.”
[Reported by Abu Dawud (4777), and it is in ‘Sahih al-Jami’ (6518)]

8 – Remember that resisting anger is one of the signs of righteousness:
{“And march forth in the way to forgiveness from your Lord, and for a Paradise as wide as the heavens and the earth, prepared for the righteous; those who spend in prosperity and in adversity, repress anger, and pardon men. Verily, Allah loves the good-doers.”}
[Al ‘Imran; 134]

9 – Submit to reminders:
Ibn ‘Abbas narrated:
“A man sought permission to speak to ‘Umar bin al-Khattab, then he said: “O Ibn al-Khattab, you are not giving us much and you are not judging fairly between us.” ‘Umar was so angry that he was about to attack the man, but al-Hurr bin Qays – who was one of those present – said: “O Commander of the Believers! Allah said to His Prophet: {“Show forgiveness, enjoin what is good, and turn away from the foolish.”} [al-A’raf; 199], and this man is one of the foolish.” By Allah, ‘Umar could go no further after al-Hurr had recited this verse to him, as he a man who was careful to adhere to the Book of Allah.”
[‘Fath al-Bari’; 4/304]

…as opposed to how one of the hypocrites reacted when one of the Companions said to him: “Seek refuge with Allah from the Devil,” So, he replied: “Do you think I am crazy? Go away!”
[‘Fath al-Bari’; 1/465]

10 – Remember the bad effects of anger:
‘Alqamah bin Wa’il narrated:
“My father said to me: “I was sitting with the Prophet, when a man came to him leading another man by a rope. He said: “O Messenger of Allah, this man killed my brother.” The Messenger of Allah asked him, “Did you kill him?” He said: “Yes, I killed him.” He asked: “How did you kill him?” He said: “He and I were hitting a tree to make the leaves fall for animal feed, and then he insulted me, so I struck him on the side of the head with an axe and killed him.””
[‘Sahih Muslim’; # 1307]