Work and train. Hard. Most as possible. Both physically, technically and mentally (being mature in game and knowing situation).
That's what you can do to get better on sports, plus the experience you already have (though it doesn't mean there is still little to learn).
Train hard everyday, that's the most you can do.
Also, follow your dream with ambition, for instance, I have a great childhood friend who became a coach (secondary) at the age of 15 on the local team (on the portuguese 1st division).
And don't forget you must keep your ambition and keep yourself from losing motivation so you don't stop training.
As an example, I'm now doing: 1000 jump ropes, 10 km running, 20min powerball and 300 swings everyday, as preparation for my next tennis tournament (12th July) while I'm injured. (I'll still do it when I get better)
Anyways, just do it, and do it the best you can. Soccer is a great sport and I love the teamwork part, the atmosphere on the team whenever you win (even more in case you win something big) is just great. On tennis, we celebrate alone, not that fun.
Good luck.
