We might start by focusing on quality of life. A high quality life would generally include good health, a fulfilling career, financial security, a good social life, and a living environment that's clean, attractive and safe.
Owning a home, or, better yet, a piece of land, is a standard sign of success.
A good education also contributes to quality of life, and philosophers place an even higher value on intelligence and the capacity for rational thought.
Yes, children have traditionally been regarded as a sign of success - in fact, they're considered a virtual necessity in some cultures.
As others have pointed out, physical attractiveness is primarily an attribute of heredity, not success. On the other hand, physical appearance is correlated with success. At the same time, people can sometimes modify their appearance through exercise, a proper diet, "dressing for success," etc.
But population growth and ever advancing technology have changed the dynamics. Some people don't consider big families politically correct.
One could argue that a big family can make an individual more successful at the expense of other families who are ultimately competing for resources.