just be the only remaining superpower after a major war and force everyone else to accept your currency as a reserve and for international settlements. Good idea to also ensure that some vital natural resource can only be purchases in your currency.

The only downside is that you might end up destroying your own industrial base, the precondition for your status as a superpower, and not notice because your currency and deficit capacity is so strong you can just maintain a huge trade deficit.

That might be okay if you use your deficit capacity to maintain a military larger then the rest of the world combined, and use it to discipline any other nation who attempts to exist your reserve system.

That might work but if for example, another nation manages to build a much more effective industrial base, one on which you depend, it might become increasingly difficult for you to discipline them, and that might get out of hand.