Honestly, for a beginner, the amount of resources to practice from and the huge number of platforms available is overwhelming. So I have decided to stick to one place and keep practicing consistently. SPOJ seemed like a really good place and so did the UVa problem collection to hone skills. Atcoder contests are good but solutions are in japanese :/ , leetcode contests are relatively easier.

I want to improve my problem-solving skills and I have a year of free time, what best practices would you guys suggest ? should I pick a tag and solve different problems to learn the technique? or just pick CF div2 contests, upsolve the problems and learn by doing that? what is the fastest way to become good at this stuff?