Absolute sway.... That's a tough one, as what I would write about would inspire people to realize their innate gifts and inner resources - but having absolute sway would by definition override that intention.
No one can make another person grow in strength and maturity to go through their challenges. It can only come from within each individual. I would not even want to 'make another person' do anything, as I deeply respect that everyone has their own path and timing. I would not overrule the beliefs and choices of another even if I had the power.
If someone comes to me with a question, or asks for help, that is different. Then I would go to great lengths to respond and gladly - because it also uses well my own gifts. And on a deeper level we are all one. Helping another in this way is not even unselfish, as it also helps me.
Back to your question, well, I *am* writing what I would write about! It is not with a motive to change the world or any person, but simply to put out my truth. I love to read comments that my writing has touched someone - and love to take the connections further when it is meant to be - but I no longer try to make this happen. I have learned to not attempt to sway others, rather to go through my own processes of growing in spiritual maturity and writing from the heart. That also happens to be the best I can do 'for the world.'