Don't worry you will definitely get good marks this time. The reason for failing might by different as you have not Studied well or there might be any other issue .We all know that 12 th result is very crucial for us .As per latest guidelines of government dates for compartment exams have not been decided due to covid19  , in that case you might have to appear for private examination.

For studying proper , study the subject thoroughly with ncert and prefer previous compartment paper for better understanding and practice .

Hope you will definitely score good marks this time.

All the best .