Hi cadiguzel.

From what I have seen, non native speakers often over estimate the degree to which their non native familiarity with English is affecting their SC answering skills. GMAT SC is a reasoning game that can be challenging for native speakers as well. So while being a non native speaker may be making SC somewhat more challenging for you than it would be were you a native speaker, likely part of or much of what is going on is that you are experiencing the same challenges that anyone does regardless of his or her language background.

What have you done so far to train for SC?