When I was around 20, my mother was visiting and I was listening to some Deep Purple. She sang along with one of the verses and then looked at me quizzically and said, "Funny... you hated that song when you were a baby." She was floored when I told her it heavily influenced my guitar playing.
To this day we wonder if being exposed to it as a baby, liked or otherwise, triggered a subconscious recognition that resulted in me liking, and actually being influenced by the music afterall.
Also, loving music is the best motivator towards being a great musician. You can help by exposing someone to different types of good music and helping to identify a favorite.
If you mean to help an existing musician to grow their fan base: - jump on some shy tik tok bandwagon, - Instagram stories, - live Q&A's