The Low Hanging Fruit
The "low-hanging fruit" is a phrase more often heard in business than in farming, because it's great good guideline for making a good investment decision. The low-hanging fruit is easy to reach. If you pick these easy pieces of fruit first, then conceivably you might be full before having to do any of the really hard work. In business circles, that state of events is called a high return-on-investment situation.
WHAT PART TO STUDY FIRST?
Since the GMAT is an adaptive test, there is no effective limit on how hard it can get. The quant section has been cracked - and professional teachers are on the edge of their seats to see what the GMAT will do to repair the hole in the score ceiling. But in verbal the ceiling is still intact, and very few people get a perfect score. That means there is effectively no limit to the topics you can study. And therefore you really need to find the low-hanging fruit, if you're to get in and out of this project in fewer than 5 years.