what are the things we should keep in mind while solving the problems of charged spherical surfaces(charges distributed in concenric circles) ??

first of all, read the question carefully and understand what is being asked. Mostly the question will ask you to find the electric field due to distribution then you apply the relevant formula. If the potential difference or energy is asked then also apply the relevant equation. You basically have to read the question properly and read the chapter too and practice lots of question so that you know which approach is right for every question :)