Now I am a pupil programmer with a max rating of 1375. Due to some physical problem, I could not continue practices. I had solved more than 100 problems in UV an online judge and solved more than 80 CSES problems on Graph, Tree, DP, and Searching and solved approximately 300 problems in code forces.

Now I am in 4th year in BSc Engineering. So need to improve my problem-solving skills in the shortest time. How can I improve myself on problem-solving in the shortest time? Which topics need to focus on?