I gave a lot of mock exams ..
4 of Kaplan ..Scores not worth mentioning, but this was when i just started to study in mid September.
Then I gave the 800 score exams.
Got very varied scores
1) 620
2) 640
3) 650
4) 740
5) 650.
After this i went on to give the Manhattan Guide exams
1) 580
2) 650
3) 670
And then the PowerPrep and the Gmatprep
Powerprep 1) 660 2) 6707
Gmatprep 1) 680 2) 740
and then gave many repeats of Gmatprep scores varied from 710 - 780
For CR i suggest you use the "elimination method" ... You have to understand what exactly the GMAT questions expects from you. The more exams you give the more you understand.
Most of the times the most obvious choice is not the correct choice. You have to understand the tricks. Spend some time analyzing the answers you get wrong in the Gmatprep and the pattern it uses. It is not about how many questions u solve but it is about how you learn from your mistakes.
For RC ..... It is just practise and above all it is the concentration you display on the D-Day. In my case I was very tired in the last half hour of the Verbal section and just went through the motions and it cost me.
In the hindsight i think i could have easily scored 5 points more in the Verbal section.
I suggest you give atleast 3 full-length exams with the AWA.
Please let me know if you need any more help.