First of all you should have to believe that this dammn thing is not a big high fi thing & secondly you can do it provided you take some time out of your daily routine for this challange
Also the preparation depends on your routine scheduling, if you are working some where then weekends will be the time for a complete go and a hour or two on daily basis.
If you are not having a job then you are a lucky person and take advantage of this.
First of all have a look of this threadeverything-you-need-to-prepare-for-the-gmat-revised-77983.html
You should also look at this one:gmat-faq-frequently-asked-questions-about-gmat-75809.html
Now after having a detailed know how of the test, just think some target date for your test depending upon your own conditions (job, study etc).
The next step is to dip yourself in the sea by taking a diagnostic test, it can be MBA.com's GMAT prep tool (which is free), the link of this tool is :gmatprep-gmat-prep-powerprep-power-prep-free-tests-77548.html
You can also check the Manhattan free test:http://www.manhattangmat.com/gmat-prep-global-home.cfm
After the daignostic tests, you can have your weak areas infront of you. Then it will be the time for all your study material. Start with OG and also keep in touch with GMATclub, this site provides a hell of a help
Make your practise on all the tests available on this site
and last but not the least,, Practice, Practice & Practice is the key!!!
Best of luck!!!!
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