Need help with improving quality of songs and the ability to bring my ideas into reality.

Hello guys. So I'm pretty decent with music theory and decently can play the keyboard. But I believe the ideas in my mind are not exactly being brought to the canvas. Maybe it's coz I don't know how to make the full use of all different tools in Garageband.

How do I learn different techniques to make my music sound more professional and full. And how to practice so that I bring my ideas into reality as close as possible. Is there any youtuber that teaches professional level on garbage band? Not beginner stuff.

Thankyou