Here is how you should divide your time when writing the essay section on the SAT:
5 minutes in the beginning for brainstorming: use this time to write down everything that comes to mind related to your essay topic, and be sure to dig into your pre-prepared examples! Once you’ve got a good list of ideas, pick or condense them down to just three (or fewer) that are strongest, and that you can write most strongly about.
20 minutes for the writing: Once you know exactly what you want to write about, get down to writing the essay. Remember to print legibly, but get it down FAST. Make sure your essay is organized before you write, and separate ideas and points into different paragraphs—with good transition phrases between them.
The last few minutes for proofreading: Got back through your work and check over your essay, fixing any errors, missing words, or awkward phrases you can before time is up, and adding in missing transitions or clarifications where you can. Polish your work as well as you can.
Keep in mind that you’re being graded on the quality of a first draft of an essay—the graders know it’ll be messy and have some small spelling/grammar errors. But they’ll also want to see that you can persuasively and coherently argue a position.
SAT Prep Plan: SAT Tips 
