Sentence Correction

I have already taken the GMAT once and scored in the 73% in the verbal, I am taking it again with a much stronger Math base but still I cannot seem to get the Sentence Correction down. The SC is the only part of the verbal I can't get.... I'm taking the test in 2 weeks, I know I will not be able to master all the SC, but are there a few specific errors I should look out for that can at least prevent me from ruining my verbal score totally assuming I can pick up the slack on the CR and RC.... I have used all the study guides, even did some tutoring, for some reason the SC just doesn't stick with me.. thanks for your help....

just do a book on english grammar fundamentals....that will help you ..