The first step to become good at competitive programming is to learn classes. They are complex and provide a great introduction into competitive programming because they are always used. Most of the people who don't know classes are newbies, so if you know them you are automatically a pupil. Once you are familiar with classes, you need to learn Quicksort. Quicksort is very useful because you have to sort all the time in competitive programming and using a sort function from the C++ Standard library is inefficient. This will easily make you a specialist. To be an expert, the only major topic you need to know is centroid decomposition. This is an advanced topic, but it appears very often. Learning this will allow you to reach expert in no time. Expert is one of the top ranks, so once you reach it, you can be sure you are among the best of the best. I hope you take my advice and become one of the greatest competitive programmers of all time.