For youth basketball officials, teaching is as important as whistling fouls and violations. Young players don't fully understand many of the rules so you should explain your calls to the players as you go--within reason. But remember, you will need to keep the game moving and not hold a rules clinic every time there's a violation or foul.
Have a little latitude with your calls unless there is a question of safety. It's okay to warn a player that he or she should be careful about committing a violation or a foul. Make sure you explain to the offending player the correct way to do something so that you won't have to blow your whistle. If the problem persists, however, you must make the call. Discuss such repeated problems with the coach during a break in the action, and let the coach take care of it from there.
Keep in mind, though, that you are not the coach. It's okay to teach, but you should avoid coaching the players.
Feel free to offer a brief word of praise for a great play, such as, "nice shot," "good job" or "great pass." Avoid anything that might denigrate other players, such as, "he sure couldn't guard you" or "you're the best player out here."
Be friendly and approachable but maintain your authority. The players should feel comfortable asking you questions and you should be open to answering them in a non-condescending and easily understandable manner.
On the other hand, if a player becomes a problem and mouths off to you, tell the player that his or her behavior is not acceptable. Report the youngster to the coach if the problem persists.