Hello,
SRCC is one of the top colleges of Universisty of Delhi and one need to score high percentage in class 12th to get admission in this college. Cutoff of SRCC is always high.
To score good percentage in Class 12th, you will have to work hard. You should make  a schedule to study and follow it religiously.
You should be regular in studies and concentrate on every subject. Focus on NCERT books, try to solve every question and practice as much questions as you can.
You can refer to other books like U-like and solve previous year question papers and sample papers during the last few months.
Complete your syllabus on time and go fully preparaed for the pre-board examination conducted by the school.It will help you to analyze your preparation.
Try to manage your time effectively and balance your preparation. If you are taking coaching classes then it is important to give time to self study also. Self study is very essential.
Don't take stress. Limit yourself from distractions. Stay positive, motivated and dedicated towards your studies.
Hope for the best.
Good Luck!