How do you choose a strong argument for an assignment?

I usually start with the question itself rather than trying to write the introduction right away. Once I know what I actually want to argue, finding examples and evidence becomes much easier. I’ve also found that a useful source of ideas for argumentative assignments can save a lot of time when I’m stuck between several possible angles. I still check the sources myself, though, because an interesting idea is only useful if I can support it with solid evidence.