The brutal reality is this: Ghostwriting is an expensive service. That's just the way it is. Therefore, it's in your financial self interest to at least try to become your own ghostwriter. You have nothing to lose and hundreds of thousands of dollars to hold onto.
The first step in this DIY project is to decide who you want to be on the printed or digital page. That's called your "persona." The medium of writing demands that you create the voice, rhythm, organization style, kinds of evidence presented and word choice which all come together in that one persona or writing self.
No, it isn't you. Writing, an art which was discovered centuries ago, requires a more formal self. That's part of the reason so many find writing so hard: It's an artifical way to communicate.
So, how do you select your writing self? Essentially you investigate what aggregate will serve you the best in achieving your goals. They may range from fundraising to developing a trusted presence in work. Then you search for how others are achieving those goals through the kinds of prose they use. You leverage them as models, cherry picking what aspects of that will be an appropriate fit for you.
Soon you have the main ingredients for your writing self.
In part 2, you will learn how to try out that persona.