Returning an object in C++

I am learning C++ from a background of mostly C and Java and I am curious on what is the best way to return an object in C++ without having to copy the object. From my understanding, C++11 introduced rvalue references (&&) to move data from a temporary variable (as oppose to copying). Example:

std::string getStr(){
   return "Hello";
}

std::string &&hello = getStr();

Another way I could think of is using a shared pointer.

std::tr1::shared_ptr<std::string> getStr(){

    std::tr1::shared_ptr<std::string> hello(new std::string("Hello"));
    return hello;

}

auto hello = getStr();

I am thinking maybe an rvalue reference is better but I'd like a second opinion first before I use it. Which is better?

Also is it recommended that fields in a class be rvalue references if they won't be set using the constructor? Example:

class StringHolder{

   public:
     std::string &&str;
};

StringHolder sh;
sh.str = getStr();

Thank you guys very much!