I think that the realization of someone (and consequently happiness) is something that is strongly linked to 2 things: transformation and awareness of this transformation. If you are able to make great personal and world transformations and are aware of your progress and your usefulness to other people, you are closer to that goal. If you are not accomplished enough, no matter what the subject is, it is because you have not yet been able to make the necessary transformation to make it happen, either personally or in the capacity to change the world and the lives of people through your existence.

I guess mentally and physically healthy is at least a huge step in order to be happy in life (for me at least).

It is a broad topic hard to clarify in few lines, but put it simple life fulfillment is the capacity to serve own core value in their lifetime. In person, I would prefer to choose a course to settle me down in mentality. 

To me, you can't really be fulfilled if all you can come up with are things that are basically only related to you and what you do or what you get or what you want to be. I think that living a fulfilled life means to go beyond your own self and let your life mingle with that of other people by influencing them, learning with them, helping and getting helped, these things.

I don't think you can say that you lived a fulfilled life or that your life is fulfilled when it can't even get past your ego. A life that's also lived in benefit of others is the most fulfilling type of life, because when others -- and not just yourself -- can say you've lived such a life, that's what matters.

Peace