how to improve my score from 590 to 720 levels in 1 month

Thanks Kraken for your reply.

In preparatory exam my individual scores were as follows:

1) SC 8 of 16 correct
2) RC 7 of 13 correct
3) CR 7 of 12 correct

This implies that i usually get 22 or 23 correct answers.
I have 50 to 60 percent accuracy i want to increase that accuracy in each section to about 80 to 90 percent.
I know that laying stress on SC will improve my score but please suggest RC and CR improvement techniques also.
I usually take 10 minutes to complete a lengthy passage and 8 min to complete a short one.
So a lot of time goes into RC reading which is a pain.

Following are my pain areas

1) SC,CR,RC accuracy only 50 to 60 percent
2) Never been able to complete my paper on time. I had only 3 minutes for last 5 GMAT verbal questions.Time management costed my dearly both in QA and verbal.
3) RC takes lot of time to read.
4) I usually get nervous if i go behind schedule.

I want to increase my accuracy in each are about 80 to 90 percent.
and better time management. Please guide