Do virtual contests

Solve problems of rating up to 1200 , since Div2 B can go up to 1200 rating, and as can be seen from your profile, you have mainly solved problems of 800-1000, you need to step out of your comfort zone and focus on 1100-1200. And to become a pupil, you have to solve Div2 A,B fast or solve Div2 A,B,C. So just try to solve problems up to 1200 and try to do them fast. Hard work is the only option. So try at least 30 problems of 1100 and 1200 and then you would surely see a positive change.