not confident with sc part.any shortcuts to understand sc topics and improve score in 26 days
I must say that I can help you on this query.
If you can't mull over theory or rules of SC, then pick up GMATPrep questions PDF, start solving the questions under timed conditions, and google your queries.
While googling queries check the best explanation on internet for a particular question. Most probably the best explanation you will encounter will be from RON(Manhattan/God of SC).
Note the types of questions which come over and over, major questions would be from ||ism and modifiers and verb consistency.
GMATPrep PDF (SC) has some 600 questions.
I did approx 370 questions from that document in last 15 days before exam, and yes it contributed to me.
Being a non-native, I can advise only above to you.
Lastly, MEANING is more important than grammar structure of the sentence.
FIRST= understand the meaning
SECOND=understand the structure
THIRD=Identify the errors
Hope that helps
I Assisted You => KUDOS Please