What is the best strategy to prepare for GMAT AWA section?

The best strategy will be to practice writing/typing essays in a simulated environment. You can practice online with arguments similar to actual GMAT ones and use the online free evaluator to gauge your preparation. http://www.gmatawa.com . You get a composite score on a scale of 6 as well as a break-up of your performance on 3 parameters of coherence, structure and vocabulary.