One of the most important things for a young football player to learn is how to tackle with proper form. Bad tackling form can result in you missing the tackle, or worse, can result in serious injury.
See What You Hit
If you're a defender about to make a tackle, a very natural thing for you to do is to close your eyes, put your head down, and throw yourself at the ball carrier. Unfortunately, this tendency is one of the worst things you can do. Instead of closing your eyes, you need to see what you hit. Your head should be back so that the back of your helmet can touch the top of your shoulder pads. Your eyes need to be open and your feet need to drive you through the tackle. If you can see your defender upon impact, you're much more likely to make a solid tackle from that point on.
Seeing what you hit is a vital piece of advice for young football players. It's a critical skill to learn, no matter what your position or age level.