Spending more time reading the first and last paragraph, while scanning the middle paragraphs is a useful strategy, as long as you have a sense of how the middle paragraphs relate to the passage.
Not getting bogged down in the inevitable details of the middle paragraphs should help you shave 12 minutes down to 10 minutes.
Of course the time you spend answering questions can also slow you down. Having a strong sense of the passage when you read through it first, so that you are able to anticipate the answers to questions and quickly find the relevant part of the passage, will help immensely.
Here is post I wrote dissecting this technique in more depth. http://magoosh.com/gmat/2011/gmat-readi ... rehension/
Let me know if I can answer any other questions
Magoosh Test Prep