The key to AWA is to adhere to a good structure for your essay. I recommend:
- Intro
- 3 paragraphs (make each about a supporting point/example)
- Conclusion
The biggest dangers are (1) you don't plan at all and just start writing (take first 5 minutes to write an outline!), or (2) you don't finish and don't write a conclusion.
Otherwise, you might want to throw in some stuff about recent events, references to books, etc. I found that reading the Wall Street Journal and other newspapers was good preparation for me for the last 1 month before the test. The Economist was useful too. Basically just making sure my mind was active and used to reading QUALITY writing, since I had been out of school for 6 years.
If you take the online FREE practice test from Princeton Review, then you can pay like $5 to get one of their people to grade your essays. Best GMAT deal out there. I did this, and got a 5 on the essays. I thought they really sucked, but the person pointed out that I needed to "have a conclusion for full marks" and that made me realize it was more important to get the essays finished than to make them perfect.
The result? Got a 6.0 on AWA on real test. And my essays were far from perfect. So, the key (like the rest of the GMAT) is to learn to work the system and give them what they want....
Good luck!
Marcus