As a former athlete myself, being motivated helped me accomplish plenty of tasks and goals. The problem was that I wasn't always excited about completing the task I needed to improve each day. Motivation, Dreams and Goal setting wont be enough so I want to give you some things to think about on your journey.
Build great habits: Write down a list of things and tasks you need to perform each day to improve. For example, three times a week (M,W,F), I will work on my angle breaks coming out of a backpedal at 6PM or I will work to catch 50 footballs each day to improve my hand/eye coordination. Add those to your habits of brushing your teeth, eating, etc
Build system: A system is a group of activities that work together to achieve a set goal by a certain day. For example, I wake up, Brush my teeth, say a prayer, eat my breakfast, read for a bit, go to school, drink my protein shake, attend practice, etc. The system you create should be easy to perform consistently and fun to do
Build Discipline: As I explained earlier, your motivation may not be working all the time and that is when your discipline has to take over. You create discipline when you create your system and consistently give in to your good habits. You will battle with the new changes early but after a while, the task will become your makeup.
Build a great support group: Get around the people who will encourage you, challenge you and keep you focused on the journey. Your crowd is important and can really help you advance to the next level in sports as well as life. Be around people with a similar drive like you.