7:45 PM, Monday April 20th 2020
I'm not sure of any exercises that would necessarily help with this, but at least conceptually there is one thing you absolutely need to continually remind yourself of: every single action you perform is the result of choice. Whether or not that choice is a conscious one is the problem, and making more purposeful choices is itself something that we improve on over time, as long as we do so... well, consciously.
Your choice to hesitate before putting a mark down is a choice you are making. You second-guess your preparation out of the fear of a negative result. The solution here is not to believe in your abilities, to trust in the idea that "you've got this" and "you can do it". The solution is to choose to accept that the second your pen touches the page, any opportunity to avoid a mistake that may or may not happen has now passed. Whether or not you put the stroke down accurately is no longer within your control. What is within your control however is whether or not you choose to hesitate (and therefore eliminate any chance of having a smooth stroke) or whether you choose to push through with confidence, putting the mark down.
The ghosting method's strengths are not just in the fact that you're made to run through the stroke several times before committing it to the paper. Instead, it actually lies in the idea that each of the three stages has its own responsibilities and goals, and they can be treated as different people working in an assembly line in a factory.
The first person is responsible for identifying the specific mark that needs to be drawn, what task this mark needs to accomplish, which angle of approach would be most comfortable, and determining whether the mark you want to make is the best for the given task.
The second person in the line is responsible for getting your muscles accustomed to the motion required to make this mark. They're unconcerned with the how's and why's, and don't care if those things are correct. The motion required was determined already, its job is simply to get your muscles ready to execute it.
Finally, the third in the line is responsible for making a single, smooth, confident stroke. They're not responsible for accuracy, for how closely you reproduce that planned, prepared motion. It's just to make a simple stroke - and you know you can make a smooth stroke because if you go to a page and draw them as quickly as you can without even thinking about which stroke you want to make, they'll come out smoothly. Their job is just to make the mark with no hesitation, because they have nothing to hesitate about.
Now, it's easier said than done to put your mind in the shoes of each of these individual workers, to focus on just doing that individual, simple task, at any given point. But to do so is a choice, and to worry about the stage preceding where you are now, is also a choice.
So, long story short - take responsibility for the choices you make. If your marks are inaccurate, that's not that big of a deal. Flow and smooth execution is first and foremost your priority, and only once that is nailed down does accuracy become a concern.
You're not alone in your struggles with this, and if you want to talk to people who struggle through similar issues, you may want to join us on the drawabox discord chat server. Talking with others who are at various points along a similar trajectory may help you see a path forward.