GMAT Verbal Section | Help needed to improve verbal

Hi All,
I have just started my preparation for GMAT and taken the 1st GMATPrep test. I scored590.

Q50
V20(SC : 8/18, CR: 8/10, RC: 5/13)

My verbal is at extremely poor condition specially SC and RC. Please guide me to improve the same to at least 35. I am planning to take GMAT test on 1 week of this November.

More info: I am a non-native speaker.
Thanks
Manoj
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