To be a good C++ programming you need to understand constructors, destructors, inheritance and pointers (as a bare minimum). Once you know how those things work then start coding. Start small and simple like creating text based games. ie build choose your own adventure type games where text is displayed on the screen and you need to make a choice with the keyboard to decide which path to take. Planing and executing on a full game (even a simple one like this) can be a big task and it will teach you how to structure code so that you can reuse parts.
Once you are comfortable working with char's, int's, std::strings start to investigate the other parts of the standard template library. vectors, maps, queues, lists etc. Then try building a 2d text based game like tick-tac-toe or connect 4. This will teach you how to program things that uses arrays.
Now you can start looking at graphics, to improve upon the previous games that you have under your belt.