Here are some QuickTips that apply to both Analytical Writing sections.
1. Be sure to include brief introductory and concluding paragraphs, which are consistent with each other and with the paragraphs in the body of your essay.
2. Your essay must at least appear to be well organized. Use transition words and phrases to help the reader follow the flow of your discussion.
3. Compose your introductory paragraph last—after you've completed the rest of your essay. Why? Because you essay might evolve somewhat from your initial plan; if you've composed your introduction first, you might need to rewrite it.
4. For every point you make in a GMAT essay, always provide a reason and/or an example to support that point!
5. Pay close attention to writing mechanics—grammar, sentence construction, word usage and diction (whether you've used the right word for the right job). It doesn't matter if your essay contains brilliant ideas if you can't express them. In short: It's form over substance!!
6. It's okay to refer to yourself in your essays—at your option. Just don't overdo it. Phrases such as "I think," "it is my opinion that" and "in my view" are superfluous and a waste of your typing time.
7. Don't try to impress the reader with your vocabulary. There's nothing wrong with demonstrating a strong vocabulary. Just don't overdo it; otherwise the readers will suspect that you're using big words as a smokescreen for poor content.