How do you build an elite NBA championship contender? Well one way is luck. For example the San Antonio Spurs who just happen to have won the NBA lottery the Robinson, Duncan, and Wemby years. Another way is location. NBA players love Los Angeles and Miami, so the Lakers, Clippers, and Heat will always have an advantage when it comes to signing free agents, or in this player empowerment era getting players to force trade there. And the last and final way is probably the hardest. That's a front office being great at their jobs.
The Boston Celtics had that for decades when Red Auerbach simply ran circles around the other teams' general managers.