Week 1

Go through the ETS Official Guide for GMAT, specifically a description of the GMAT test.
If you like, take a mock test to see where you stand.

Week 2

Find school grammar books and brush up on your grammar. The GMAT English focuses on grammar, not vocabulary.

Week 3

Use the Math Review section in the Official Guide for GMAT to brush up your math concepts.

Week 4

Start practising math problems topic by topic. Identify the areas where you need more practice. The official guide has more than 400 solved math problems.

Week 5

Now that you have revised your grammar, start with the sentence correction section of the verbal portion of the test. Practise from the official guide.

Week 6

Progress to the critical reasoning section from the official guide.

Week 7

Dedicate this entire week to the reading comprehension and the essay writing component of the test. Use the essay topics from the official guide.

Week 8

Practise mixed math problems from all topics. If you need more help, consider getting school textbooks and practise from there as well.

Week 9

You are now ready to practise an entire GMAT test at one stretch. Make sure there are
no distractions around you. Time yourself. Try and finish one test per day. Use the paper tests from the ETS official guide, but avoid repeating the tests.

Week 10

Practise the Computer Adaptive Tests CDs -- Powerprep and online software. You will
now have the confidence to take the GMAT exam at the testing centre.