In no certain order...
1) Find a role model
Find a few. Find as many as you need. Find one for skill x, another for skill y, etc. There are no limits, no rules.
I believe you have to see someone, dream of being them, then maybe even catching and beating them. By doing this, you will force yourself to level up whatever skill it is that you see in this person, because it's a) on your mind and when its on your mind b) you will start to copy the behavior. It wont be perfect, but it will be improvement. And with enough improvement, 1% improvement everyday, that's momentum and action and you're on your way to becoming.
2) Have an Imagination
This goes right along w the above. A lot of us just watched episodes 1&2 of the MJ documentary. Do you know how many kids grew up imagining they were Mike?
Kobe did. Probably 80% of the current NBA did too.
So whatever your sport, find your MJ and imagine you are him.
3) If You Really Want It, Get Obsessed
A lot of coaches, leaders, quote masters have said "You get out, what you put in," (I think thats the quote). It's true and unless you are the 1% of the 1% of the 1%, its absolutely true. If you train only when the weather is nice, only when your machine is open, only when you're in the mood or only when coach says it's mandatory, you will not be very good and will not reach your potential.
Be obsessed.
Right now, a lot of young people are on their own for training, so what will you/they do? Wait for school to open and coach to call? Or get an edge on the "competition," now?
If you want to reach your peak, if you want to optimize your time and experience, you have to go all in, and do it in every way you can think of. That's nutrition, that's proper sleep, that's training, that's film study, that's reaching out for advice, everything. No stone un-turned. Lift, run, stretch, walk, sprint, train your mind to be tougher than ever...
4) Train Your Mind
My middle daughter, Livi, wants to play high school volleyball and we were talking the other day about training. She asked what the Eastside girls used to do. I told her "It was half physical, half mental..." She wondered about the mental.
I would add a variety of elements to any random session to spark an emotional reaction. Totally intentional every time. Reason being, shit happens. Game or life, shit happens and we have to regain focus and rally back. The only way to do that when it matters is to practice it.
One of the greatest tools you can have is to be able to do this to yourself. You wont be able to surprise yourself with a sudden drill you didn't see coming, but you can choose to do some of the hardest drills possible and hold yourself accountable to perform as absolutely best as possible.
Set your own personal goals for physical achievement, even from session to session. Find a set of stairs and time yourself to the top, how long did it take? Now go back down, recover for 30 seconds and repeat 14 more times, all trying to beat the preceding sprint.
Be Obsessed with beating your time. What would your role model do? Imagine it.
Training your mind is everything. Laser focus to execute the task at hand and that task should be alignment with x goal. If it is not, you need to change the task or the goal. Otherwise you are wasting time. Read that again.
If the task at hand is not in alignment with the goal, either your task/drill/practice is wrong, or your goal is wrong. The choice is yours to pick.