To revise a piece of creative writing, I recommend making three separate passes through the work: once for substance, once for style, and once for conventions.
How to revise the substance of your work will depend on exactly what type of writing it is. If it is a work of fiction that has a story arc--such as a short story, drama, novella, or novel--you should begin by looking at each piece of the story arc separately to see if it can be improved. For example:
Setting/Characters: Is there a clear sense of time and place in the work? Are the characters engaging? Have you used indirect characterization to help the reader get to know your character--such as describing how the character looks, what the character does, what other people say about the character, what the character says and what she says about herself, and how others react to the character? In addition, if your point of view allows it, have you described what the character thinks and how he feels? Have you used direct characterization to describe the character? This can be acceptable if done in an interesting way, but it should be kept to a minimum.
Inciting Incident: Is there a clear event that introduces the conflict and begins the action? Does it come relatively close to the beginning of the story? Should you try to move it closer to the beginning?
Conflict: Make sure the conflict is clear. Is there a way to intensify it? Is it too predictable? If so, can you add a twist or turn?
Climax: Does the action and conflict reach a high point? Revise this part to make it even more exciting and momentous.
Denouement: Are all loose ends tied up neatly (unless you deliberately want to leave some things ambiguous at the end)? Is the ending satisfying for the reader?
You can also work to add in some literary elements that will enhance the story, such as symbolism, foreshadowing, and verbal, dramatic, or situational irony. In addition, you should look for any parts of the story that don't add to the conflict or characterization. Delete any superfluous passages. Look for a balance of dialogue and description, and add more of one or the other if necessary.
Once you have tightened up your story arc, proceed to read the story through once again, this time for style. Look especially at verbs. Using active, powerful verbs will make your writing pop more than anything else you can do. Make sure your nouns are specific and concrete rather than abstract. Cut out wordiness. Vary sentence openers in your descriptive passages. Make sure your dialogue sounds realistic. Read it aloud to test it. Make sure you have kept your point of view consistent.
Finally, in your third pass over the story, look carefully at all word usage, grammar, spelling, punctuation and capitalization. Make sure you have kept your verb tenses consistent. Make corrections as necessary.
Depending on the length of your work, this may take you several sessions. Even when you have finished this process, you may want to set the work aside for days or weeks, then come back to it and repeat the process again. Remember, the difference between poor writing and excellent writing lies in the post-writing process. Don't skimp on this step; it is the best way to ensure you have a finished piece to be proud of!
Creative writing assignments will always possess a level of subjectivity. If you truly believe in your work, you will sojourn on regardless of what anyone says. However, since you have asked for feedback, I offer my thoughts.
If I can voice one area of critique, it would be that you have many different moving parts to this. You are going for quite a bit in one piece and this result in losing some readers. There is the awesome force of nature, the philosophically profound reality of death, and then there is the existential crisis of purpose. Each of these could form their own creative writing assignment. It is difficult to balance all three in one piece and do enough justice to their exploration. I don't know where you would go with this, but the reality is that all three together don't necessarily complement one another because they are so profound and lend themselves to so much introspection. Given how the force of nature seems to be so dominant in the story, this might be where you go and then try to work everything else into this theme. However, I think that the philosophical divergence in the story is an area that has to be revisited.
In terms of the work itself, I think that the opening is strong. However, I tend to think that you might want to punctuate so many natural elements with a personalized approach. For example, in describing the initial storm, it might have more of an impact on the reader if you were to insert a personal approach. This might mean interjecting some of the subjective actions in the midst of this natural element. However, I think that you end up focusing so much on the natural elements to open the story that the human introduction is muted as a result.
I think that the transition from the different storm elements needs to be clearer. There is the initial storm to open the story, the image of then-president Bush with storms in Alabama, and then the focus on the sister. These transitions are a bit too quick. Given the forceful nature of each, I think that you might need to spend some time breaking them down to allow the reader a moment to process and follow along with you in the narrative. At a certain point, there is so much thrown at the reader that following the narrative frame of reference becomes lost. Given what the piece is trying to do, it might not be the best for the reader to be so forlorn.
I understand what is being done in the ending. However, I don't think it really meshes well with the philosophical voice that has been established. For example, the death of the speaker seems to cave into cliches. The overused expression of "one last time" for the heart beat, "Slump" and "my body hits the floor," almost lessen the experience. These expressions seem to undermine the strong philosophical tone established in the beginning. I think that the final note about how the speaker laments that there is "no one to remember me" and life "ending at the bottom of a ship" seems to belie the strong and awesome power of nature. Individual human beings are merely part of the natural setting that has been so forcefully established throughout the piece. I think that ending in a way where the human voice seems to transcend all denies the opening of the piece and its crux (that nature's power is awe-inspiring). Perhaps more continuity could be established if the ending were to mirror some of the elements featured in the opening.