Generic thoughts:

Treat all players as if they are going on to the next level. Attempt to give them all the necessary skills. Never assume that the player is too fat, too slow, too clumsy. They may shed those labels with age, and it would be great if they were skilled!!

Be analytical, not critical. Give praise. Do this with body language also. If they see disappointment on your face or body position, they will get the message.

A defender does not have to win the ball. If she is limiting an attacker's time, space and options, she is defending.

A coach who is genuinely interested in the well being of his players, is fair, honest, stern, willing to keep them on the edge, they'll never forget him.