Hi Tino21
I'm sorry about your score. Based off your post, I assume you're interested in retaking the GMAT?
If so, I'm going to focus on SC, since this seems to be a known weakness. Here are a few tips:
1. Patience: Don’t jump the gun. You need to go through many steps before you will be ready to answer the hardest SC questions.
2. Meaning: The problems with SC questions rarely are only grammatical. You should always be sure you understand what meaning the original sentence is trying to convey. This will allow you to rule out answer choices that don’t make sense or violate the intended logic and meaning of the sentence.
3. Attention to detail: Work on steadily scanning a line, comparing two sentences and noticing small details such as an added or missing ‘s’ or a comma.
4. Trust the method : In other words, don't solely rely on a gut feeling or 'ear.' Eliminate incorrect answer choices systematically, and based on a hierarchy of error types (grammatical and logical errors before stylistic errors and ambiguity). The Economist GMAT tutor goes through this process extensively.
If you're interested, sign up for a free trial, and you can see how the Economist GMAT Tutor can help you improve SC, CR and other sections that you're concerned about:
https://econgm.at/freetrialoffer.
Hope this helps and best of luck!
Jessica