Ask HN: Help with getting C++ developer job

Little bit of background: I have 3 years job experience as maintenance developer giving patches to banking product. I work in Java and C code base, but it is mostly legacy code and most of my work required knowing banking well than the technicalities of code itself

My question: I want to get out of the company and want to get job as C++ developer. What should my plan be and what are the things i should concentrate on. Please help me with concepts i should be thorough in, any resources i can use to get better.

Appreciate your help. Thanks :)