This will be a short post but I want to give a special emphasis to my least favorite statistic (maybe). I do not like on-ball steals. This is a risky play and can often lead to getting beat and also drawing fouls. The best place to get steals is on poor passes (never gambling though).
If a player is in good help-side defense they can jump a pass and get a steal if they read the play properly. Another great emphasis that I place is for players to deny once the ball is dead. What this means is that when I ball handler picks up their dribble they are no longer a threat to drive. This means that once we see this, we pick up our man in a full denial.
The next type of defense that you need to emphasize with your players is off-ball defense. I will often refer to this type of defense as help-side defense. If you have a player get beat when on-ball, having defenders ready ad able to stop penetration will be a huge benefit to your team. Teaching players what position they need to be in and how to rotate when helping on defense will take your teams to the next level.
Some teams are able to stay glued on to their defensive assignment and have no breakdowns but we are not one of those teams and I have never had one of those teams. The main teaching point that I emphasize when working with off-ball defense is that players must always see both their man and the ball.
Here are some other teaching points that I bring up when implementing off-ball defensive fundamentals:
If your player is one pass away, you are around 2/3 of the way over and helping down.
If your player is two passes away you need to get at least one foot in the paint to be in position to help.
Side front the low-post.
Play behind the high post.
If your athlete is on the opposite side of the court, you need to be at the midway point of the court.