In terms of what to cut, I'd say this paragraph, or at least half of it, could be the first to go. Your essay is about writing, but here you go off on a tangent about debate. If you desperately want to keep it, then I'd say keep only the first and second sentences. The third sentence confused me the first time I read it, and while after a few rereads it makes sense, I don't think it really adds anything to your essay. It's one of those almost melodramatic elements that mainly add length to the piece.
But still these doubts creep in, and even with immediate and frantic attempts to lay them to rest, they seem to creep deeper
Another example, I think, of the purely dramatic.
enough that either my instructors or the small community that reads
Can't decide whether it's grammatically correct to say read or reads in that case...
The more I reflect on it the more I realize that doubt is always rearing its ugly head in some form or another, the things we wish to excel at will never be free of this curse.
Also largely sentimental. Creative, yes. But an admissions officer who already read hundreds of essays may be thinking "Get on with it, already."
as he laughs at the feeble attempts of a boy playing at being a man.
You say "he" here, as well as in your first paragraph. But in the first few sentences of this paragraph, you use "it."
Doubt is what drives me to work, doubt is what drives me to sadness, doubt is what drives me every failure and moment of weakness, and, most of all, doubt is what drives me to every success.
I might rearrange this sentence to better transition from the negativity of doubt in the first half of your essay, to the positive in the next. "Doubt is what drives me to sadness, doubt is what drives me to every failure and moment of weakness, but, nevertheless, doubt is what drives me to work, and, most of all, doubt is what drives me to every success."
However, doubt also gives rise
You're not really contradicting your point in the previous paragraph, so "however" doesn't really fit here, I think. I would write Doubt, therefore, gives rise...
who I can become if I'm not careful.
I'm not sure what you mean by who you could become. Who CAN you become? Did I miss it or did you not explain it?
Here is a version of your essay with most (if not all) of my comments and suggestions added. Its down to 770 words from 1005, and I think still has most of the meaning the first draft did. By the way, after spending so much time reading this, I think there might be one way to make your essay better. You're dealing largely with the intangible, a concept that affects your life. It MIGHT be worth grounding it with a specific event or experience. For instance, a moment where you overcame doubt, and found the success you spoke of. Where and how you would place that in, I couldn't say. You'd probably need to take a lot of the dramatic stuff out, even what I left, and reorganize/rewrite a good portion of it. Whether that's worth it, you be the judge.
There is nothing in this world as internally exhausting as doubt of oneself.
My experience with doubt cannot be easily grouped into one story or memory, for I've skirmished with it many times over the years, each of us taking to our trenches and trading shots until, inevitably, I drive him away from the mental battleground for a few weeks. But he returns. Usually in the wake of an essay I didn't do well on or an inability to put words down on a page at home. These are small occurrences, and the practical and reasonable part of me calls out, saying that I shouldn't despair, but the deeper emotional part is plagued by the horrible: doubt.
I feel a doubt that I can't write, a doubt that everything that I put onto paper is puerile prose as a vehicle for wholly adolescent ideas. It is the doubt that a talent I once had, a talent I've always been told I had, has faded; that somehow I have atrophied and like a body-builder awakening from a coma, I can no longer wield the tools that once defined me.
The thought of plateauing permanently at the age of 17 is as appalling to an aspiring author as paralysis is to a star athlete.
The only real way to put these doubts to rest is to write a piece of fiction or an essay good-enough that either my instructors or the small community that reads my work gives positive feedback. Writers are that way, and I have absolutely no shame in saying that as far as my work goes, I am a creature who is a slave to pride and vanity. However, even these moments of brief peace are not totally free of doubt, as somewhere, deep within my brain I hear distant echoes of, "they're just saying that! They don't want to hurt your feelings." Or, "these people don't read you seriously enough to give you real feedback, they picked out some words they liked skimming it, that's your feedback."
Even now, as I write and I see words scuttle onto the screen in front of me like inky spiders, I feel doubt lurking. I feel it waiting for every misplaced comma and overwrought metaphor, for every overly self-pitying phrase and every pathetic clause. I feel it pacing up and down the lanes of my essays, carelessly evaluating and tossing phrases agonizingly crafted aside as he laughs at the feeble attempts of a boy playing at being a man.
Doubt is what drives me to sadness, doubt is what drives me to every failure and moment of weakness, but, nevertheless, doubt is what drives me to work, and, most of all, doubt is what drives me to every success.
The only thing that truly maintains talent is fear of losing it; arrogance and hubris are curses which will rob a runner of his speed, a politician of his charm, or a writer of his pen.
Doubt, therefore, gives rise to the steely human resolve to write and try, resolve which can only exist and have meaning in the face of doubt. Resolve which arises with its knightly aura only after the voice in my head repeatedly tells me that I can't, that I'm not good enough. A rebellious streak offers me an armored hand and a stern look, "you can."
And I cannot disappoint.
Rising above every petty and scared desire, combating and conquering every impulsive urge to give up, this is what makes writing worth it. It is the feeling of triumph and resolve over all our baggage, all our personal monsters and skeletons in our closet. It is the closest I can get to facing pure fear, the closest I can get to staring into the abyss and emerging with my heart and ideas intact. Doubt exists for me to conquer, every silenced insult, every firmly punctuated sentence and every pride-filled line drives me and defines me. It constantly reinforces who I am and who I want to be, and, most importantly, who I can become if I'm not careful.
Doubt is a monster which lives in our hearts and consumes us, its voracious appetite is the most exhausting thing I can think to face, and yet, I wouldn't trade it for the world. Doubts callous laughter and pitying gaze, its patronizing tone borrowed from every pseudo-intellectual, and its grating constant critique are the integral key to my resolve and drive. Doubt may hurt, but it's what makes me who I am, it allows me to do what I do, and, most of all, it allows me to write.