1. Can fly the aircraft with experience and confidence.
2. Doesn't interfere unduly when FO is handling (Refer to 1)
3. Is courteous to all of his crew and passengers.
4. Knows when he really has to say something to the IFD or FO or take control.
5. Sets an example by dressing correctly as prescribed by his company by, for instance, wearing his cap when appropriate and wearing a long-sleeved shirt when he 'kin well likes!*
* Have to say that, if you do, you really have to be careful that the vent doesn't get caught on the thrust levers (The only reason I can see for doing away with long-sleeved shirts on the flight deck).