When you win 11 championships, 5 MVPs, have 12 All-Star appearances and are in the rare club of having an NCAA championship, NBA championship, and Olympic gold medal, you know a thing or two about winning. Oh yeah, the Finals MVP award is named after you as well.
Bill Rusell was not only one of the most dominant players ever, but he was also one of the best teammates ever. He made everyone around him better and often sacrificed individual shine and numbers for the benefit of the team. He proved his understanding of basketball not only as a player but also as a player-coach and a coach.
We could analyze his game and try to extract his basketball philosophy from it, but there's no need. In 1956 Russell published an article in Sports Illustrated (the whole thing is a fascinating read) and within that article, he structured his Laws of Basketball (via SI):
Russell's First Law: You must make the other player do what you want him to do. How? You must start him thinking. If he is thinking instead of doing, he is yours. There is no time in basketball to think: "This has happened; this is what I must do next." In the amount of time it takes to think through that semicolon, it is already too late.
Russell's Second Law: You got to have the killer instinct. If you do not have it, forget about basketball and go into social psychology or something. If you sometimes wonder if you've got it, you ain't got it. No pussycats, please. The killer instinct, by my definition, is the ability to spot—and exploit—a weakness in your opponent. There are psychological subrules in this category.
Russell's Third Law: Be cute but not cuddly. I mean, you should be nice at all times, but there is a lot to be said for an elbow in the chops when all else fails. This is forceful psychology. Last resort stuff.
Russell's Final Law: Remember that basketball is a game of habit. In getting good at it, we develop certain habits. Therefore, if you make a player deviate from his habits—by psyching him—you've got him.
His ability to encapture the physical and mental aspects of the game in so little words is fascinating. No accident he was so dominant in his time.