The secular people I know pretty much universally share some, many or all of the the following characteristics, which I cite in no particular order.
A respect for truth - sadly a respect not shared by many of the religious.
A life affirming stance, and a general acceptance of the idea that the very transitory nature of life makes it the more precious.
A fascination with understanding, as best they can, life, the universe and everything, and accepting the implications for their personal survival after death of their growing understanding.
Courage in the face of their forthcoming personal oblivion.
A will to good, without hope of reward, or fear of punishment, in any putative hereafter.
A sense of deep awe and wonder when contemplating the wonders of life, the universe and everything.
A sense of ethics.
A sense of wonder and awe faced with the greatest creations of mankind, in the fields of science, music, literature et al.
It's good to have something to live up to... ;)