There’s no substitute for lots of practice I’m afraid! Make small games at first and gradually start trying new things, you’ll learn your way around soon enough 
Don’t expect overnight results though, it takes a few months before you can get totally comfortable. Some background knowledge in C++ helps too, I used CPP Insitute when I was first starting out. However, there’s no need to go crazy learning traditional C++ if you don’t need it - Unreal will only throw you off else.
I never learnt regular C++, only Unreal C++