Good suggestions by Rob.
In my gmat exam score was 270 so I will plan to give exam in December .
So please any know me how to increase my score upto 600.
And any best book for me.
Well frankly speaking your English needs hell lot of improvement. Your sentence was framed very very awkward. Reaching to 600 level will require a lot of time and persistence. I'd strongly recommend that you start reading newspapers and magazines first and also learn grammar and then actually be worried about CR and RC