Keeping your body properly hydrated is vital when playing sport. This is especially true for youngsters, whose bodies are still growing and developing. A lack of water can cause players to become drowsy and dehydrated. The cure is the simple act of drinking water. As a coach, it's a basic tip to make sure your players are drinking water.
Take plenty of water bottles with you and spread them around the field during training sessions and have them handy in scrimmages so you can let players drink when they need to.
When the weather is hot it is easy to drink water. In the colder months, drinking water takes more of an effort, but drinking adequate amounts is just as important.
One of my players often brings a flask of hot chocolate on cold days, but this is no substitute for water and does not replace the fluids lost during physical activity.