I learnt a good bit of C++ by going through Elements of Programming Interviews, trawling through cppreference.com and getting help from #C++ on FreeNode for the difficult parts. Coming from mainly functional languages, I actually found it quite fun going through cppreference.com and seeing all the interesting ways in which C++ does things. Especially the STL.

Pick an interesting project and continue in that vein. The biggest difficulty for me was understanding the memory model and all the different types of value, references and so on, but #C++ was again a brilliant resource for smart pointers to good articles on the difficult subjects.

Professional C++ programmers might have other opinions on how best to learn.