Understand the amount of training required to become a professional athlete.
Football is a team sport and requires teamwork, because this is not a one-person game. Teamwork Teamwork Teamwork!!!
Don't forget your original intention.
Make yourself to be a team leader or an important position.
Never give up even you are not tall or strong. Try to highlight your characteristics.
I used to play pro in Mexico and I suppose that the process can be a little different.
Here you can start playing in a FC at any age since studying is not a requirement. But I would say that the steps to overcome and get where you want are pretty similar...
The best advice I can give you is to become an athlete. Nowadays it is not enough to be good at something if you don't make the best of it, so you must train hard 6/7 to excel. Work on you technique, take care of your body, have a healthy life... go big for it so you don´t have regrets later.
Also, something that helped me a lot was how motivated I always was. I was always giving my all, every training every minute of the match. That helped me a lot to become better every day and also had a great impact in my teammates. I'm sure that if you work hard and if you show great results, you can get wherever you want.
Always remember to be a team player and try to improve your leadership skills. Be nice to everyone and let your game speak for you. You don't have to demonstrate anything to anyone but yourself. Be punctual, get habits that could help you develop your career and set realistic objectives.
Make your relationship with coaches something special, make yourself unforgettable for them... If they like your game, they will speak great about you and someday could help you grow your career.
Hope this helps.