Jacob had it. Esau didn't.  Symbolically, we can look to Jacob's wrestling match with the angel.  Those who have class have wrestled with their own personal "angel" and won a victory that marks them thereafter.

Class never makes excuses.  It takes its lumps and learns from past mistakes.

Class is considerate of others.  It knows that good manners are nothing more than a series of petty sacifices.

Class bespeaks an aristocracy that has nothing to do with ancestors or money.  The most affluent blueblood can be totally without class while the descendant of a Welsh miner may ooze class from every pore.

Class never tries to build itself up by tearing others down.

Class is already up and need not strive to look better by making others look worse.

Class can "walk with kings and keep its virtue, and talk with crowds and keep the common touch."  Everyone is comfortable with the person who has class--because he is comfortable with himself.

If you have class, you don't need much of anything else.  If you don't have it, no matter what else you have--it doesn't make much difference.