How to Be Courageous in Islam
Question

What is courage according to Islam? How can a person become courageous?
Praise be to Allah.The concept of courage in Islam
“Courage in Islam refers to steadfastness in the heart at the time of danger." (Tahdhib Al-Lughah (1/214); Lisan Al-‘Arab 8/173)
In real terms, courage refers to:
Steadfastness of the heart at times of calamity , and remaining calm when faced with frightening situations. 
Ibn Al-Qayyim (may Allah have mercy on him) said:
“Many people may confuse courage with physical strength, but they are two different things. Courage is steadfastness in the heart when faced with calamity, even if one is physically weak.
[Abu Bakr] As-Siddiq (may Allah be pleased with him) was the most courageous of this Ummah after the Messenger of Allah (blessings and peace of Allah be upon him), although ‘Umar and others were physically stronger than him. But he surpassed all the Companions in his steadfastness of heart in every situation in which mountains would tremble. In those situations, he was steadfast at heart and calm, and the courageous ones among the Companions and their heroes would turn to him, and he would calm them down and encourage them." (Al-Furusiyyah  p. 500)
He (may Allah have mercy on him) also said:
“Courage comes from the heart; it is steadfastness and calm at times of fear. It is a characteristic that results from patience and positive thinking, for when a person thinks that he can overcome trouble and has patience to help him, he will remain steadfast.
By the same token, cowardice results from negative thinking and impatience, which makes a person think that he cannot overcome the problem and he does not have patience to keep him calm. The origin of cowardice is negative thinking and thinking that the worst will happen…" (Ar-Ruh  p. 236)
Ibn Hazm (may Allah have mercy on him) said:
“The definition of courage is: being willing to offer one’s life to defend one’s faith and womenfolk, and to defend a neighbour who has been wronged, and to defend an oppressed person who has sought your protection, and to defend someone who has been wronged with regard to his wealth and honour, or who has been wronged in any other way, whether the wrongdoers are small or great in number.
Falling short in what we have mentioned is cowardice and weakness.
Exposing one’s life to danger for the sake of worldly gains is recklessness and foolishness.
Even more foolish than that is the one who offers his life because he refuses to give people their dues, or to defend someone else who refuses to give them their dues.” (Al-Akhlaq was-Siyar  p. 32)
Prophet Muhammad was the most courageous of people 
The Messenger of Allah (blessings and peace of Allah be upon him) was the most courageous of people, as Al-Bukhari (2908) and Muslim (2307) narrated from Anas (may Allah be pleased with him), who said: The Messenger of Allah (blessings and peace of Allah be upon him) was the best of people and the most courageous of people. One night the people of Madinah were in a state of alarm, and some people went out towards the sound [that had caused the alarm]. They were met by the Messenger of Allah (blessings and peace of Allah be upon him), who was coming back, as he had already gone to investigate the matter. He was riding the horse of Abu Talhah bareback, with his sword around his neck, and he said: “Do not be afraid, do not be afraid.”
How to be courageous in Islam
There are many ways and means of developing courage, among which we may mention the following:

Being strong in faith and remaining steadfast therein.
Studying the biographies of the brave and courageous among the heroes of Islam.
Having the courage to speak the truth and tell others about it.
Having the courage to denounce evil and forbid it .
Maintaining self-control .

Abu Hurayrah (may Allah be pleased with him) narrated that the Messenger of Allah (blessings and peace of Allah be upon him) said: “The strong man is not the one who wrestles others to the ground; rather the strong man is the one who controls himself at times of anger.” (Narrated by Al-Bukhari (6114) and Muslim (2609)
Ibn Al-Athir said in An-Nihayah (may Allah have mercy on him) (2/23):
“The one who wrestles others is the one who is so strong that he cannot be thrown down. He used this phrase in the context of self-control, when suppressing one’s anger and suppressing one’s Nafs (self), because if a person controls his Nafs, he will defeat the strongest of his enemies and the worst of his opponents.” 

Respecting Islamic commandments.
Respecting the limits set by Allah.
Showing courage in situations in which courage is required.
Supporting the one who has been wronged, and striving to put a stop to the mistreatment to which he is being subjected.

And Allah knows best.