Hi rishit1080,
Including a Mistake Tracker/
Error Log throughout the course of your studies is a great choice. One of the keys to scoring at a higher level is to define WHY you're getting questions wrong. In many cases, the 'issue' will be something minor/silly - such as not taking enough notes, misreading the question, using an approach that is too complex (when another, easier approach was possible), etc. Those errors should be relatively easy to 'fix' as long as you stay focused on the 'precision' in your work. You should NEVER be doing work 'in your head' - insist on writing everything down on the pad and leave nothing to chance. The 'work' behind a typical GMAT question usually takes less than 1 minute to complete (the rest of the time is spent reading the prompt and taking notes), so you really do have enough time to deal with every prompt (even if you ultimately choose to 'dump' a question). Demand a more consistent level of 'documentation' from yourself when you work and you'd be amazed how quickly you can pick up points. To that end, when you redo questions that you've gotten wrong, you should plan to work through every step - again, write everything down - so that you never allow those little errors to creep back into your work.
GMAT assassins aren't born, they're made,
Rich