I asked many coders about increasing rating...many of them told just to solve lots of problem +/- 100 points+your codeforces rating ... i did that .But what i feels during contest time is that if i would learn some basic techniques(like prefixsum,minimum sliding window , basic combinatorics,dp sometimes for problems C,D) i could have done better...Only learning with practicing seems very slow for me ... Can someone give suggestion what should learn and which tag of problems to solve at this stage to at least get of this gray circle? TIA :)