Avoid burn out
Let the young players spend some time on other games to let loose once in a while. Learning and demonstrating new techniques can become burdensome at this age. Give them room to do their own thing and recharge for the next game. At the end of the day, they are still kids and they need time to make sense of the new challenges life throws at them.
Do not force the young ones to play all year round. People are much more driven when they choose to do something they enjoy. Let them play other sports as well. Be careful to not pressurize them about a game so much that it leads to burnout, injury, and resentment. Spend quality time with the whole team for a change. Go watch a game and eat together. Play when they want to play.
In it to win it!
If you want to promote a winning culture in the game, you need to keep working on and improving all previously learned techniques. Set high standards and commit to them. Push the players to perform to the best of their abilities dedicatedly. Instill competitiveness in each player to make sure they bring their A-game on the court. Focus on the success of the team as a whole rather than the performance of a few star players. Make the team and their win your priority every time. Do this every day and the whole team will follow suit!