Two general approaches.
1) How are you breaking it down? There are indeed a billion things between the language itself and greater concepts within computing (you could be a C++ master and never done anything with databases for example). If you are learning programming in general at the same time then it gets even worse. Or if you prefer I might not be a master of C++ syntax but can tell you everything in
https://textexpander.com/blog/the-7-most-common-types-of-errors-in-programming-and-how-to-avoid-them for general programming, where learning that, what a loop is, how not to fall into the traps of C++ that could be gone but they make it so powerful later that they have to stay... that is a far taller order.
2) Maybe simplify it for a while and then take the C++ extras a bit later. That is to say learn C and then move into all the fun object oriented stuff and fiddling with arrays that makes C++ more complicated but also so much faster and able to conceptualise.
I would also ask what your project is and if you can do smaller elements of it -- say you want to make a personal organiser homebrew (clock, world clock, address book, note taking, calculator, alarm clock...). You could focus on one of those elements fairly easily. You can do similar for most things, and if you somehow have a project that is 100% or nothing then get a new one to learn with.