What do we want our heroes and heroines to be in our stories? Reflections of those characteristics we would like to have ourselves or the better parts of our personalities perhaps? I can't see how any writer can avoid bringing some of themselves into the characters they write, but what really does matter is your characters must be their own people. They must be true to themselves.
I use character traits as the foundation of my character building. For example, if a character is stubborn, just where could that lead them? It would also have a major effect on their relationships with others (and probably do a lot of damage, unfortunately, but that could make a very good story, possibly of novel length). I worry less about how a character looks though I end up working this out later. I have got to know how my characters would act in any given situation and why. Whether they have brown hair or blue eyes strikes me as much less important to know though I do fill these details in later for longer stories. (Often in flash fiction you don't need to know at all).
So how do you go about creating your heroes and heroines? Don't forget to put in the flaws. I like the development of flawed heroes. None of us are perfect after all so the vast majority of our characters shouldn't be either. If you are writing about a perfect being,this is going to be difficult as all stories revolve about conflict. Any conflict arising from a perfect being will inevitably be on others' reactions to that being so the story should probably be from their viewpoint anyway.