Don't worry. I* am sure you can hit 700+.
I think you must Practicccccccce
a lot.
Here I recommed you
to review and to thoroughly analyze Explanations (some don't have them) of following materials:
-McGrawHill Gmat /2006.
-Kaplan 800 (Q and V) and OG10/11 ( only Verbal)
-GMAT sets (really good) and SC 1000
-Princeton (explanation is good)
-PowerPrep, Gmatprep ( to see your level)
-important web sites:
https://www.scorechase.com
https://www.litesee.com
https://www.gmatclub.com
For SC there is a book of White (author). Unfortunately I couldn't remember the name of that book.
Don't forget :RC and CR weigh more than SC. But weight of the RC is the most among them. That's why don't neglect RC and CR.
In SC TRY to identify type of mistakes there are 16-20 of them so that next time you don't make same mistakes.
But you can achieve this only by practicing a lot that's in a day at least 40 Q and 40 verbal questions with tharoughly analysing Official explanations.
This is what i know and what I read. Hope this will help u
good luck in your studies.
by the way I am also going to take GMAT at that time.