Hi pacer,
While you should be familiar with the format used for the writing sample, I wouldn't spend a lot of time trying to perfect your writing here. From our Free Q&A section:
If the school looks at your writing sample at all, it will be for one of two things: (1) to see how well you can develop an argument; and/or (2) to compare your writing style to that in your admissions essay(s). This is why it's important for you to take the LSAT writing sample seriously, and treat it like a very valid representation of your writing abilities.
For some law school applicants, particularly those that have been out of school for a while, the writing sample might be a rather difficult part of the LSAT. This happens for a variety of reasons:
The LSAT writing sample is administered at the end of the test, when you've already been hammering away at logical reasoning, reading comprehension, and logic games for almost three hours—and your brain is exhausted.
The LSAT writing sample gives you 35 minutes to write a cohesive, logical essay arguing in favor or against one of two equally good options (which, depending on how long you've been out of school, may seem like an impossible task—"A full handwritten essay in 35 minutes or less? That's madness!")
The LSAT writing sample is the dark horse when it comes to understanding its role in LSAT scores and law school admissions—and you know this, which can affect how you approach it.
So how is the LSAT writing sample used? It varies from school to school. Admissions committees know that you're writing the essay at the end of a grueling test, so they're not looking for polished final products—as a matter of fact, if they use it at all (and some schools don't), they are much more interested in seeing how you logically develop an idea under time constraints (a situation very similar to the myriad tests you will take in law school) than in how flowery your prose can be.
A logical follow-up question would be, "Does the LSAT writing sample affect my LSAT score?" No, it does not. Your LSAT score is determined by your answers to the questions on the LSAT, and your essay does not affect it in the least.
If you are enrolled in our Full Length LSAT course, you can find additional information about the writing sample under the Lesson and Homework Supplements to Lesson 10 - a virtual module discussing the task at hand, and 30 Writing Samples drawn from actual LSATs.
Hope this helps!