Hi Sumit,
It is definitely wise to start off with the Official guide 2016 way early in your prep rather than keeping it for the last few days before your actual GMAT. Practice using "official material" only! You may be tempted to download these PDFs that promise you tons of GMAT practice questions, but refrain yourself from doing so!
The reason being this: You need to train your mind to identify patterns on the GMAT

More about GMAT patterns here:
https://gmat.crackverbal.com/identifying ... -patterns/And honestly don't worry about exhausting practice questions. As mentioned above, you can use the Verbal review, Quant review and the GMAT prep software that contain retired GMAT questions. You will have plenty of questions to "practice" per say but really the key to a 760 GMAT score is when you sit down to analyse your mistakes.
Don't focus on getting the right answer, focus on how easily and how quickly you are able to spot the 4 wrong answer choices and eliminate them! Analysis is the key my friend. Maintain a detailed tracker where you capture all your errors and also the reasoning behind them. Practicing 1000s of questions, but not analyzing them would not be the best GMAT strategy to follow.
Take an Official GMAT practice test soon (GMAT prep software) including IR and AWA. Once you have your test scores, you will have a direction towards the areas you may want to spend more time practicing.
All the Best!