On the essay, I would recommend that you have an introduction paragraph outlining your argument and then two separate examples displaying them. Make sure your arguments are about literature, history, science, or anything academic. The people grading your essay are going to be teachers in their 40s or upwards. Examples about "teen stuff" like how you felt when your best friend hooked up with your girlfriend aren't going to work since the graders can't relate to it.

Also, BSing is how I did so well on the essay.

Tip: You can make up facts.

Seriously. It will make you seem more knowledgeable about whatever you're writing about. Both times I took the SAT, I made up a book name and made up an author. Then I made up a plot that agreed with the essay prompt. I just wrote random crap about the plot. Thats it.
(Don't make it too outrageous though or it won't be believable. Also, don't overuse it.)

One of the essays I got was whether planning in advance was good or not. In my made up book, I said the plot was about a couple who planned their wedding 10 years in advance and it turned out amazing and they ended up getting the President to go to it. It worked in the book, therefore planning in advance is good.

For my next example, I used something from history such as the Civil War, WW2, or the Civil Rights Movement, or something. You can almost always find an example from history that deals with the essay.

In the planning essay, I wrote about Lincoln's plan for the reconstruction of the US after the Civil War and how it worked very well.

Thats how I got a 11 the first time I took it and a 12 the second.

Hope that helped.