As a strength coach, through both personal experience as an athlete and having coached hundreds of kids over the past few years, I have learned that there are 3 things that really help bring out the best in an athlete through training.
1.) Understand that athletes are people before they are athletes.
You must be able to connect and empathize with them on an individual basis before expecting outstanding results. You must see and understand where they are coming from, and know their situations outside of practice and training and adapt when necessary.
Don't just host training sessions and coach them during that hour or so you have them. Reach out and check on them on days off. Go to their games and matches. Root for them. Show them you have their back.
3.) Celebrate the small victories.
This goes a long way for a kid’s confidence. If they hit a new record time, celebrate. A new Max in the weight room ..celebrate. They have a great game, then celebrate.
These small victories add up to one larger one and increase confidence along the way. And as a coach, a person of authority, you pointing out these victories will have a deep impact on self-esteem and confidence.
At the end of the day, if you are able to create more confident athlete and person, you have succeeded.