SAT Writing Please Help!!!

I got a 630 on my last SAT Test on the Writing section. I am trying to improve to a 700+ for the March test on the 14th, but am only getting 35/49 on the MC. I already finished the Erica Meltzer book last summer. How can I improve to a 43 on MC???

Learning on what you failed the most on the practice tests, like subject verb agreement, sequence of verb tenses, and idioms is a good way to start.

Thanks!