Cicero called Demosthenes “the perfect orator.” Even though he lived in the 4th Century BC and was an orator, not a writer, you can learn some important lessons from Demosthenes.
Demosthenes overcame a speech impediment and a weak voice. He took a disciplined approach to improving his speaking. You can do the same for your writing.
Your writing will get better if you work at it. Pick specific things to work on. Critique your work. Change what needs changing.
Demosthenes refused to speak on subjects he did not know well. Stick with what you know. In the world of the world wide web you could be making a mistake in front of millions.
Demosthenes refused to speak without preparation. Don’t write without preparation and process. Research, write, and revise before you publish.
As my friend Michael LeBeouf says, “The greatest truths are too important to be new.”