There are many things you can write on the topic of courage in standing up for what you believe. In light of this, let me give you some points.
First, you can talk about how it is much easier to follow the rest of the world. In other words, each society has a common sense view of the world and if you just go with the flow, then you will be accepted. This is easy. However, if you stand against the prevailing notions of the world, you will need to have courage. Here is a great quote by Michael Foucault on this topic.
"Each society has its régime of truth, its ‘general politics’ of truth: that is, the types of discourses which it accepts and makes function as truth; the mechanisms and instances which enable one to distinguish true and false statements, the means by which each is sanctioned; the techniques and procedures accorded value in the acquisition of truth; the status of those who are charged with saying what counts as true."
Second, you can also write about why the loneliness of standing for what you believe and the hard work of trying to persuade others (assuming you go that route). You might also want to use examples, like those who fought slavery in the face of those who wanted to retain the status quo.
Hmmm... Tough question!