Start with screen defence
How a team handles a simple ball screen tells you most of what you need to know about its coaching. Is the coverage consistent? Do both defenders act at the same moment? Confusion here means confusion everywhere, regardless of how the scoreboard reads.
Watch possessions begin
The first seconds after gaining possession reveal intent: do players sprint into position, or wait for the ball to arrive before organising? Teams with a plan look busy immediately. Teams without one look calm early and rushed late.
Read the substitutions
Who comes in when the game tightens, and who does not, is a direct statement of what the staff believes. It is more honest than any praise given in an interview, and it usually predicts the closing lineup in bigger games weeks later.