Hi kallia.x,
With your Score Goal, you do NOT need to correctly answer ANY of the questions that you think are too hard or too weird, but on all of the other questions, you do have to keep the little mistakes to a minimum. By extension, you have to become comfortable with the idea of 'dumping' questions on purpose - so that you'll have more time to spend on the questions that you CAN correctly answer.
Since your Official Score was relatively similar to the CAT Score you received on March 15th, we can use that prior CAT as a reference. "Review" is an exceptionally important part of the GMAT training process; your ability to define WHY you're getting questions wrong is essential to defining the areas that you need to work on (and the specific things that you need to 'fix'). As such, I'd like to know a bit more about that CAT. While a full Mistake Tracker would provide a lot more information, there are some basic questions that you should be able to answer (and the more EXACT you can be with your answers, the better):
After reviewing each section of that CAT, how many questions did you get wrong....
1) Because of a silly/little mistake?
2) Because there was some math/verbal that you just could not remember how to do?
3) Because the question was too hard?
4) Because you were low on time and had to guess?
5) How many Verbal questions did you 'narrow down to 2 choices' but still get wrong?
Based on your prior Scores (both CAT Scores and Official Scores), you almost certainly have the skills to hit 550+ right now, so you might not need much in the way of additional study materials. If you're looking for a guided Study Plan for the next few weeks, then I could put together a sub-set of the Total Score Booster Study Plan for you.
1) Have you scheduled your next Official GMAT yet (and if so, then what date is that Exam?)?
2) Going forward, how many hours do you think you can consistently study each week?
GMAT assassins aren't born, they're made,
Rich